Recently a most valued and respected Ford Six member, bubba22349 (Robert Roney), passed away which is a tremendous loss to this community. His contributions on this forum have been and will continue to have a huge and positive impact.
I had frequent contact with Bubba over the years about many Ford six subjects and my desire to own an early Mustang. I had asked him about several Mustang upgrades and so he generously spent a lot of his time creating this guide, even as his health was deteriorating, that many early Mustang owners would greatly benefit from today and into the future.
Bubba was kind, patient, helpful and very knowledgeable. Many of you remember him and for the new Mustang owners interested in upgrades this following message is Bubba at his best, still providing guidance to the Ford Six community.
https://fordsix.com/ams/in-memory-of-robert-roney-bubba22349.64/
Here it is, complements of bubba22349:
Hi bmbm40, this took me quite a while to do so I hope it helps you in your hunting for a Mustang. What you are going to find when looking for one of the early Mustangs. I.E. Note that for our discussion purposes here the 1964 1/2 models’ stock were equipped mechanically exactly the same as all of the other 1965-year models with the exception of possibly a Generator on the very first models. So, the 1965 & 1966 Six models are what I will now concentrate on to start with here. What you might find could still be totally a stock 1965 Mustang with either a 170 or a 200 Six or in a 1966 Mustang it would be a 200 Six. You may also find some a slightly modified ones too with a newer engine or even an older engine. This is what their stock equipment was and is usually what you will likely find most of the time or else there will be a mixture of the stock parts with maybe a newer 200 Engine Block and Head. What follows is LOL the "Book on Stock and Swap Transmissions for the Early Mustangs"
All the 1965 to 1966 Mustang Manual Trans Cars came stock with the smaller 132 Tooth Ring Gear on a Stepped Flywheel (often Called a Dog Dish on the Ford Six Site), these were used with the 8.5 Inch Clutch Assembly, and would of had the very small 2.77 Transmission (all these Transmissions have a Non Synchro 1st Gear) the Mustangs would of all came with the Ford Factory Floor Shifter too. Some of these early Mustangs had the optional Dagenham 4 Speeds from 1964 1/2 to 1966. Note that all 1960 to 1966 Falcon's & Comet's Six's with a Manual Trans, mostly these Cars were equipped with a Colum Shifter (3 on the Tree) but there some of the Deluxe Models like the Falcon Futura's and the Comet S22's that also had the Bucket Seats and also came with the Factory 3 Speed Floor Shifters on the Manual Trans Cars as well as many more of them that could of had the Dagenham 4 Speeds installed since they got them starting in 1962. The 1965 to 1966 Mustangs with the Dagenham Bell Housings (there are two an Early and Late) both still used the same 132 Tooth Flywheels and the 8.5-inch clutches but with a different Clutch Disk. There are two Special Made T5 Adapter Plate's that are made for them to do the T5 swap's too, most of the stock 4 Speed Six early Mustangs had the late Dagenham style Bell Housing, there is a slight possibility that some might have gotten an early Bell Swapped in them on the owner’s parts swaps. These Six Cylinder cars also used the smaller 7 1/4-inch 4 Lug Rear Axle or variations of it.
To use the T5 Trans with the Stock Parts:
There are several special T5 Adapter Plates made for all these stock Six Manual Transmission Bell Housings that were used. You mostly don't need to change much of anything inside the stock Bell Housing to use a T5 if everything is still in good condition mostly only you will only need to change out the stock 8.5 Clutch Disk to an 8.5 Inch T5 Conversion Clutch Disk that has the larger 1 1/16 inch 10 Spline Center that a T5 Input shaft has (these Conversion Clutch Disk's, are available from Modern Driveline and some others). It's very important that these stepped Flywheels need to measure exactly 1 Inch from where the Pressure Plate bolts down onto the Flywheels down to the Clutch's Friction Surface. If it’s not they need will need to be machined to that spec to have good Clutch holding for Performance as well as a longer life. There are also brand new Billet Flywheels being made (Modern Driveline has them for sale and maybe some others) and as of last several years there are several companies that are now also making Brand new 8.5 Inch Clutch Assembly's available at many places, this is great as many of those older 8.5 Clutches have been rebuilt so many time the Pressure Plates are now much thinner than they were when new.
There are a couple of Foreign Stepped type Diaphragm type Clutch units that have also worked very well they do require some Custom Machining of the stepped Distance to work correctly but are a very good alternative to using an older rebuilt unit.
The T5 also requires a special custom rear Trans Mount that are available from several sources. The stock Clutch Linkage Parts can all be reused with most of the 170 and 200 Ford Six Blocks up to around 1977 and maybe even up to 1979 or 1980 I haven't been able to verify if some of those later year Blocks after 1977, but have seen that on those 1981,1982, & 1983's blocks that were used with the cable type clutch linkage don't have the threaded Block Boss needed for the Z Bar Pivot Ball to mount to, a simple mounting plate could likely be made though. The stock Clutch Linkage maybe need some repair work if there are areas of wear showing on the Pivot Pins, I have fixed many by welding them up and grinding them back to OEM size, but there is also many of the linkage parts available new and even many of the V8 parts are the same, there is also a Rollerized set up made by Open Tracker too. The only Major Linkage Part that is harder to find is the Six Cylinder Equalizer Bar (or also called a Z Bar) they seem harder to find, and sometime people pass them off as being for a V8 engine set up. I happen to have a nice 1965 Z Bar if you need to know what they look like and what it's dimensions are, Note that the V8 Z Bars can't be used as they are since they are much shorter in width, it is likely possible to weld in a section to get them to the correct width to fit with a Six as well as also rework the Arms as needed to work.
With the stock 7 1/4 Inch Rear Axle and the 2.77 3 Speed Trans the stock Drive Shaft will at the bare minimum need a different front Yoke to Fit into the T5 there is a special Conversion one that can work on the stock drive line that uses the stock 1100 U Joints. The T5 Front Yoke used on the mid 1980's to mid 1990's 5.0 Mustangs or the Mercury Capri's are Metic Splines in them The C4 Yoke is very close to the same Spline and some people have used them. So, you can also look for the 1964 1/2 to 1966 C4 Auto Trans Driveline and that C4 yoke may work just fine, or you can use the standard T5 Yoke with a 1330 U Joint as it fits right on the front Driveline U Joint. The Length is usually quite close to being right (you would be looking for a minimum of 3/4 to a Max of 1.5 inch out) Ideally you want about 1 inch of Slide in amount before touching and bottoming out on the Transmissions Tail Housing this what I try to have if it ends up being more than the 1.5 inch you will need to have a new Drive shaft tube installed or new Driveline made to the correct length. If it’s less than the 3/4 inch of slide in than you could have that Driveline shortened up and rebalanced, I used to do these myself if you can weld or have a friend that welds, then I can also tell you how to do that.
On the C4 Auto Transmissions all of them used on the stock models in those years were the Dual Range Valve Body's (often called the Green Dot), they are ok for a stock type driver car. They are not the best for any type of performance application. The fix for performance is to upgrade them to the Select Shift Valve body by installing one out of a 1967 to 1969 C4 these Valve Bodies bolt right into them. I did a number of those swaps back in those days, I also usually added one of the TransGo 47-1 Reprogramming Kit in them for even better performance (sometimes others depending on what the planned use was going to be) along with a small Auxiliary Transmission Cooler. The later 1967 Shifter Indicator Parts will swap right into the factory stock 1964 1/2 to 1966 Mustang Floor Shifters to convert them over into a Select Shift type at a low cost. Or you could also swap in the complete 1967 to 1969 Floor shifter if you found a good one.
There are two types of C4 Transmissions that Ford used. These are the Case Fill's used in many cars and the Pan Fill types that were a little heavier duty and used in the Big Cars as well as many Trucks. Because there was only the small bolt Pattern Bell Housings made to fit the on the Ford 144, 170, or 200 Small Six's Engine Blocks up to 1981 they can only be used with a Case Fill C4 Trans. Also note that Case Fill Transmissions can come with a 6 Bolt V8 Bell Housing to Fit with the 157 Tooth Flex Plates for both the 250 Six and also on the many other SBF V8's like the 289 & 302 to name just two. These 157 Tooth V8 C4's are usally stronger internally since they would have had more clutches & Steels, they can also be used on the Smaller Six's just by removing the Front Bolt on V8 type 6 Bolt Bell Housings and installing the Small Six Bell Housing in place of it and also using the Small Six Flex Plate and Torque Convertor. These Case Fill C4's mostly all will measure the same length in the Case and Tail Housings so they will fit right into place. The early 1964 to 1969 C4's can be upgraded with many of the later parts but for Performance I like to find and use a minimum of a 1970 C4 or better still is one of the 1971 to 1981 C4 since they will have all the very best of the Ford Factory Improvements already installed in them.
Now what if you happen to find a 1965 or 1966 Mustang Six or V8 Car that was at reasonable price and it was just missing the engine and Trans? In some ways you would be little ahead of the game with a V8 Car since it had the better 5 Lug Wheels Larger Drum or Disk Brakes and the bigger 8 Inch Rear Axle with many more Rear Axle Gear Ratios available this would be ideal for a more performance build up. Note This also applies to those that want to upgrade their Small Six Cars for Higher Performance use and decided to swap in all those upgraded V8 Suspension and Brake Parts or a bigger 250 Six. All those stronger V8 Parts are a direct bolt on too.
Any of the Small Six's and even the larger 250 Sixes can be bolted right into place into the 1965 & 1966 Mustangs there are many site members that are running them. With the right parts though the 250 takes just a little more work since it’s a taller, wider, and is also a slightly longer Short Block so it needs to be set down lower into the chassis some, but it will still fit in very nicely. Someday I am hoping to be offering these 250 Six Conversion Motor Mounts for Sale as a swap Kit to help members do this conversion.
All of the above Transmissions options above will still work the same for any of the 1964 1/2, 1965, & 1966 Mustangs for those using one of the older engine blocks with a slight change in the Drive Shaft for use with the T5 and the C4 Transmissions and using the V8 8 Inch Rear Axle Combo you would also just use the 1965 or 1966 V8 C4 Auto Trans Driveshaft too. The 1969 up 250 Six engine would use the very easy to find 6 bolt V8 Bell Housing for late 289, 302 with the adaptor Plate or you could even use the Fox Chassis Cable Clutch T5 Bell Housings for a bolt in T5 Swap. The Driveshaft for a Manual Tran's such as a 3 Speed, 4 Speed, or T5 also should be very close to the same as the above and a 1965 or 1966 should be able to use the 1965 or 1966 V8 Manual Trans or C4 Auto Trans Driveline.
There are a couple other Rear Axles that can also fit the 1965 and 1966 Mustangs first is the direct bolt in of a 1965 or 1966 Mustang V8 8 Inch Axel. Then the 4 Lug 8 Inch Axel that was used in the Maverick Six's around 1971 or 72 up to 1974 was also in those same years of Comets. Also, the same goes for the 5 Lug 8-inch Axles used from 1975 to 1977 Mavericks & Comets with Six's and V8's. If you want the stronger 9 Inch there are Custom Made ones you can get or if you are able to find a 1957 to 1959 Big Ford Car, Station Wagon, Ranchero, or Sedan Delivery they will also be a bolt in. Driveshafts will probably need to be shortened some to fit with these 9 Inch Axles but for all the other the 8-inch axles it should work with the stock 1965 or 1966 Mustang V8 Drivelines. Lastly some are trying the 8.8 Rear Axles out in the Mustangs they will need a little narrowing likely this can be done by using two of the short side Axles but there are custom made axles that you can get too looks to be a good choice I am thinking about using one in that Falcon Project.
If you find a 1966 200 Six Mustang that still has the Original Block or you find a 1965 or 1966 Mustang with a 1966 or even newer 200 Six's you have a Bonus those blocks will all have the Duel Bell Housing Bolt Pattern Block's. This will open the door to another great upgrade in using the Bigger 3.03 Trans (C6 or C7 and a few others) Bell Housings with the larger 136 Tooth Flat Flywheels that also use the 9 Inch Clutches (and these can also use the biggest 9 3/8-inch Bronco and other Clutch assembles) are hard to find but they are out there. There is a 1966 3.03 Bell used in some Fords like the Fairlane's that you would be able to use the early Narrow Trans Bolt Pattern for the 3.03 3 Speeds, Top Loader 4 Speeds, and also the Borg Warner T10's, they can be found but it’s not as easy. There are T5 Adapters for them too. Much easier is to find and use one of the 1967 up C7 170 or 200 Six Bell Housings with the wider Trans Mounting Bolt Pattern there are also many more of those 3.03 3 Speed Transmissions, also the right SBF V8 Top Loader 4 Speed's bolt up too with the Correct shifter location for the Mustang's. These are more available they will work so very nice, and they will also use the most common T5 adapter Plate that many companies sell at a lower cost. Note on the 3.03 3 Speeds and Top Loaders they must have the correct Shifter location to work in the Mustangs which has shifter setting farther back than those used in the Falcons and Comets there are some Transmissions that will have both, but many don't having only one or the other. If you need help in that let me know.
The front Spring towers can sometimes use some straightening up as their Towers can be sagging inward after all these years and or from front or side collision damages found even more so on the V8 Cars but also the Six's that have been worked really hard during their lifetimes. I discovered this way back in the later 1970's on my 1966 Mustang 2 + 2 Fastback that I was working on it would not handle very well. Was the very worse Mustang I ever had of many of them. Turns out looking over the car that it had been hit really hard on the driver’s side at one time. They had replaced all the bolt on suspension parts and the fender on that side but did nothing about the damaged done to the spring tower. After getting that back straight again and doing some extra reinforcement Plates and stich welding this was just like Ford did on the 1969 & 1970 Boss 302 and 429's for Racing use, plus an expert Wheel Alignment that car turned into the very Best Handling Mustang I ever had. If you are interested in hearing more about that let me know.
After that this is where I start rebuilding the front suspensions. A good inexpensive upgrade that you can do yourself is the Roller Spring Shock Mounts. There is an easy way to free up the Upper Control Arms when rebuilding a front suspension. There are also the Full Rollerized Front suspension Parts by Open Tracker too. For those that want to go farther there are the several other front Suspension set ups from TCI using the Mustang II, Pinto Parts, or the Strut type setups using the Fox Chassis Parts.
Back to the stock type setups a Six can use the 1965 / 1966 V8 GT Springs if you want the suspension to be a little stiffer and there is 3/4-inch Front Sway bar that is excellent with an aftermarket 5/8-inch Rear sway bar, or you could also use a 7/8 inch front and a 3/4 inch rear if you want it stiffer yet. For Mustangs without Power Steering a Rollerized Idler Arm really helps a lot when driving at slower speeds and in parking. With all the many improvements in Wheels and Tire Tech an expert Wheel Alignment to the right specs is very important for great Handling. Ask me if you need those specs and or need info on the size of Wheels and tire that can fit these Mustangs many the Alignment shops today don't know how to do this set up right.
For the Front Spindles there are those nice 4 and 5 Lug Disk Brake Set ups made by Scott Drake and some others for use with the stock Six Spindles. There are some advantages though to using the stock Mustang V8 Spindles to with the Better Steering Geometry there is even a stronger Aftermarket Granada spec Big Bearing Spindle with the corrected Geometry for use on the 1965 and 1966 Mustangs. There are also the Dual Piston Disk Brake Kits that are copies of Ford Kelsey Hays Disk Brakes that the early Mustang sued they are very nice.
Chassis upgrades for a Car that will be doing duty on Auto Cross, Road Track and Drag Racing as well as High Performance Street Cars looking for the best in cornering. First with the stock front suspension the best Mod that is almost free is the Shelby / Arning Upper Control Arm Drop. It used to be that there were some free Templets on the net to do this, but they have recently disappeared. I still know how to make my own templet or there are several that can be bought. It’s been written about many times on the site, so I won't put it here unless you want me to. Next is using the Export Brace, fairly reasonable to buy or many are making their own custom ones that can provide some extra clearance for a Multi Carb Intake set up. Monte Carlo Bars used to be made special in a Six Cylinder Spec Bar, but haven seen them lately but wouldn't be too difficult to build one of them. A set of the Sub Frame Connectors is great way to stiffen up the Chassis some, along with a sheet metal plate installed behind the Rear Seat Back sealing off the truck space on the Coupes or Convertibles.
Well that is about the majority of it, I may think of some more yet or if you have other questions let me know.
*I put this in the 144-250 performance section but could belong in Mustang Corral so Mods move where they think appropriate.
I had frequent contact with Bubba over the years about many Ford six subjects and my desire to own an early Mustang. I had asked him about several Mustang upgrades and so he generously spent a lot of his time creating this guide, even as his health was deteriorating, that many early Mustang owners would greatly benefit from today and into the future.
Bubba was kind, patient, helpful and very knowledgeable. Many of you remember him and for the new Mustang owners interested in upgrades this following message is Bubba at his best, still providing guidance to the Ford Six community.
https://fordsix.com/ams/in-memory-of-robert-roney-bubba22349.64/
Here it is, complements of bubba22349:
Hi bmbm40, this took me quite a while to do so I hope it helps you in your hunting for a Mustang. What you are going to find when looking for one of the early Mustangs. I.E. Note that for our discussion purposes here the 1964 1/2 models’ stock were equipped mechanically exactly the same as all of the other 1965-year models with the exception of possibly a Generator on the very first models. So, the 1965 & 1966 Six models are what I will now concentrate on to start with here. What you might find could still be totally a stock 1965 Mustang with either a 170 or a 200 Six or in a 1966 Mustang it would be a 200 Six. You may also find some a slightly modified ones too with a newer engine or even an older engine. This is what their stock equipment was and is usually what you will likely find most of the time or else there will be a mixture of the stock parts with maybe a newer 200 Engine Block and Head. What follows is LOL the "Book on Stock and Swap Transmissions for the Early Mustangs"
All the 1965 to 1966 Mustang Manual Trans Cars came stock with the smaller 132 Tooth Ring Gear on a Stepped Flywheel (often Called a Dog Dish on the Ford Six Site), these were used with the 8.5 Inch Clutch Assembly, and would of had the very small 2.77 Transmission (all these Transmissions have a Non Synchro 1st Gear) the Mustangs would of all came with the Ford Factory Floor Shifter too. Some of these early Mustangs had the optional Dagenham 4 Speeds from 1964 1/2 to 1966. Note that all 1960 to 1966 Falcon's & Comet's Six's with a Manual Trans, mostly these Cars were equipped with a Colum Shifter (3 on the Tree) but there some of the Deluxe Models like the Falcon Futura's and the Comet S22's that also had the Bucket Seats and also came with the Factory 3 Speed Floor Shifters on the Manual Trans Cars as well as many more of them that could of had the Dagenham 4 Speeds installed since they got them starting in 1962. The 1965 to 1966 Mustangs with the Dagenham Bell Housings (there are two an Early and Late) both still used the same 132 Tooth Flywheels and the 8.5-inch clutches but with a different Clutch Disk. There are two Special Made T5 Adapter Plate's that are made for them to do the T5 swap's too, most of the stock 4 Speed Six early Mustangs had the late Dagenham style Bell Housing, there is a slight possibility that some might have gotten an early Bell Swapped in them on the owner’s parts swaps. These Six Cylinder cars also used the smaller 7 1/4-inch 4 Lug Rear Axle or variations of it.
To use the T5 Trans with the Stock Parts:
There are several special T5 Adapter Plates made for all these stock Six Manual Transmission Bell Housings that were used. You mostly don't need to change much of anything inside the stock Bell Housing to use a T5 if everything is still in good condition mostly only you will only need to change out the stock 8.5 Clutch Disk to an 8.5 Inch T5 Conversion Clutch Disk that has the larger 1 1/16 inch 10 Spline Center that a T5 Input shaft has (these Conversion Clutch Disk's, are available from Modern Driveline and some others). It's very important that these stepped Flywheels need to measure exactly 1 Inch from where the Pressure Plate bolts down onto the Flywheels down to the Clutch's Friction Surface. If it’s not they need will need to be machined to that spec to have good Clutch holding for Performance as well as a longer life. There are also brand new Billet Flywheels being made (Modern Driveline has them for sale and maybe some others) and as of last several years there are several companies that are now also making Brand new 8.5 Inch Clutch Assembly's available at many places, this is great as many of those older 8.5 Clutches have been rebuilt so many time the Pressure Plates are now much thinner than they were when new.
There are a couple of Foreign Stepped type Diaphragm type Clutch units that have also worked very well they do require some Custom Machining of the stepped Distance to work correctly but are a very good alternative to using an older rebuilt unit.
The T5 also requires a special custom rear Trans Mount that are available from several sources. The stock Clutch Linkage Parts can all be reused with most of the 170 and 200 Ford Six Blocks up to around 1977 and maybe even up to 1979 or 1980 I haven't been able to verify if some of those later year Blocks after 1977, but have seen that on those 1981,1982, & 1983's blocks that were used with the cable type clutch linkage don't have the threaded Block Boss needed for the Z Bar Pivot Ball to mount to, a simple mounting plate could likely be made though. The stock Clutch Linkage maybe need some repair work if there are areas of wear showing on the Pivot Pins, I have fixed many by welding them up and grinding them back to OEM size, but there is also many of the linkage parts available new and even many of the V8 parts are the same, there is also a Rollerized set up made by Open Tracker too. The only Major Linkage Part that is harder to find is the Six Cylinder Equalizer Bar (or also called a Z Bar) they seem harder to find, and sometime people pass them off as being for a V8 engine set up. I happen to have a nice 1965 Z Bar if you need to know what they look like and what it's dimensions are, Note that the V8 Z Bars can't be used as they are since they are much shorter in width, it is likely possible to weld in a section to get them to the correct width to fit with a Six as well as also rework the Arms as needed to work.
With the stock 7 1/4 Inch Rear Axle and the 2.77 3 Speed Trans the stock Drive Shaft will at the bare minimum need a different front Yoke to Fit into the T5 there is a special Conversion one that can work on the stock drive line that uses the stock 1100 U Joints. The T5 Front Yoke used on the mid 1980's to mid 1990's 5.0 Mustangs or the Mercury Capri's are Metic Splines in them The C4 Yoke is very close to the same Spline and some people have used them. So, you can also look for the 1964 1/2 to 1966 C4 Auto Trans Driveline and that C4 yoke may work just fine, or you can use the standard T5 Yoke with a 1330 U Joint as it fits right on the front Driveline U Joint. The Length is usually quite close to being right (you would be looking for a minimum of 3/4 to a Max of 1.5 inch out) Ideally you want about 1 inch of Slide in amount before touching and bottoming out on the Transmissions Tail Housing this what I try to have if it ends up being more than the 1.5 inch you will need to have a new Drive shaft tube installed or new Driveline made to the correct length. If it’s less than the 3/4 inch of slide in than you could have that Driveline shortened up and rebalanced, I used to do these myself if you can weld or have a friend that welds, then I can also tell you how to do that.
On the C4 Auto Transmissions all of them used on the stock models in those years were the Dual Range Valve Body's (often called the Green Dot), they are ok for a stock type driver car. They are not the best for any type of performance application. The fix for performance is to upgrade them to the Select Shift Valve body by installing one out of a 1967 to 1969 C4 these Valve Bodies bolt right into them. I did a number of those swaps back in those days, I also usually added one of the TransGo 47-1 Reprogramming Kit in them for even better performance (sometimes others depending on what the planned use was going to be) along with a small Auxiliary Transmission Cooler. The later 1967 Shifter Indicator Parts will swap right into the factory stock 1964 1/2 to 1966 Mustang Floor Shifters to convert them over into a Select Shift type at a low cost. Or you could also swap in the complete 1967 to 1969 Floor shifter if you found a good one.
There are two types of C4 Transmissions that Ford used. These are the Case Fill's used in many cars and the Pan Fill types that were a little heavier duty and used in the Big Cars as well as many Trucks. Because there was only the small bolt Pattern Bell Housings made to fit the on the Ford 144, 170, or 200 Small Six's Engine Blocks up to 1981 they can only be used with a Case Fill C4 Trans. Also note that Case Fill Transmissions can come with a 6 Bolt V8 Bell Housing to Fit with the 157 Tooth Flex Plates for both the 250 Six and also on the many other SBF V8's like the 289 & 302 to name just two. These 157 Tooth V8 C4's are usally stronger internally since they would have had more clutches & Steels, they can also be used on the Smaller Six's just by removing the Front Bolt on V8 type 6 Bolt Bell Housings and installing the Small Six Bell Housing in place of it and also using the Small Six Flex Plate and Torque Convertor. These Case Fill C4's mostly all will measure the same length in the Case and Tail Housings so they will fit right into place. The early 1964 to 1969 C4's can be upgraded with many of the later parts but for Performance I like to find and use a minimum of a 1970 C4 or better still is one of the 1971 to 1981 C4 since they will have all the very best of the Ford Factory Improvements already installed in them.
Now what if you happen to find a 1965 or 1966 Mustang Six or V8 Car that was at reasonable price and it was just missing the engine and Trans? In some ways you would be little ahead of the game with a V8 Car since it had the better 5 Lug Wheels Larger Drum or Disk Brakes and the bigger 8 Inch Rear Axle with many more Rear Axle Gear Ratios available this would be ideal for a more performance build up. Note This also applies to those that want to upgrade their Small Six Cars for Higher Performance use and decided to swap in all those upgraded V8 Suspension and Brake Parts or a bigger 250 Six. All those stronger V8 Parts are a direct bolt on too.
Any of the Small Six's and even the larger 250 Sixes can be bolted right into place into the 1965 & 1966 Mustangs there are many site members that are running them. With the right parts though the 250 takes just a little more work since it’s a taller, wider, and is also a slightly longer Short Block so it needs to be set down lower into the chassis some, but it will still fit in very nicely. Someday I am hoping to be offering these 250 Six Conversion Motor Mounts for Sale as a swap Kit to help members do this conversion.
All of the above Transmissions options above will still work the same for any of the 1964 1/2, 1965, & 1966 Mustangs for those using one of the older engine blocks with a slight change in the Drive Shaft for use with the T5 and the C4 Transmissions and using the V8 8 Inch Rear Axle Combo you would also just use the 1965 or 1966 V8 C4 Auto Trans Driveshaft too. The 1969 up 250 Six engine would use the very easy to find 6 bolt V8 Bell Housing for late 289, 302 with the adaptor Plate or you could even use the Fox Chassis Cable Clutch T5 Bell Housings for a bolt in T5 Swap. The Driveshaft for a Manual Tran's such as a 3 Speed, 4 Speed, or T5 also should be very close to the same as the above and a 1965 or 1966 should be able to use the 1965 or 1966 V8 Manual Trans or C4 Auto Trans Driveline.
There are a couple other Rear Axles that can also fit the 1965 and 1966 Mustangs first is the direct bolt in of a 1965 or 1966 Mustang V8 8 Inch Axel. Then the 4 Lug 8 Inch Axel that was used in the Maverick Six's around 1971 or 72 up to 1974 was also in those same years of Comets. Also, the same goes for the 5 Lug 8-inch Axles used from 1975 to 1977 Mavericks & Comets with Six's and V8's. If you want the stronger 9 Inch there are Custom Made ones you can get or if you are able to find a 1957 to 1959 Big Ford Car, Station Wagon, Ranchero, or Sedan Delivery they will also be a bolt in. Driveshafts will probably need to be shortened some to fit with these 9 Inch Axles but for all the other the 8-inch axles it should work with the stock 1965 or 1966 Mustang V8 Drivelines. Lastly some are trying the 8.8 Rear Axles out in the Mustangs they will need a little narrowing likely this can be done by using two of the short side Axles but there are custom made axles that you can get too looks to be a good choice I am thinking about using one in that Falcon Project.
If you find a 1966 200 Six Mustang that still has the Original Block or you find a 1965 or 1966 Mustang with a 1966 or even newer 200 Six's you have a Bonus those blocks will all have the Duel Bell Housing Bolt Pattern Block's. This will open the door to another great upgrade in using the Bigger 3.03 Trans (C6 or C7 and a few others) Bell Housings with the larger 136 Tooth Flat Flywheels that also use the 9 Inch Clutches (and these can also use the biggest 9 3/8-inch Bronco and other Clutch assembles) are hard to find but they are out there. There is a 1966 3.03 Bell used in some Fords like the Fairlane's that you would be able to use the early Narrow Trans Bolt Pattern for the 3.03 3 Speeds, Top Loader 4 Speeds, and also the Borg Warner T10's, they can be found but it’s not as easy. There are T5 Adapters for them too. Much easier is to find and use one of the 1967 up C7 170 or 200 Six Bell Housings with the wider Trans Mounting Bolt Pattern there are also many more of those 3.03 3 Speed Transmissions, also the right SBF V8 Top Loader 4 Speed's bolt up too with the Correct shifter location for the Mustang's. These are more available they will work so very nice, and they will also use the most common T5 adapter Plate that many companies sell at a lower cost. Note on the 3.03 3 Speeds and Top Loaders they must have the correct Shifter location to work in the Mustangs which has shifter setting farther back than those used in the Falcons and Comets there are some Transmissions that will have both, but many don't having only one or the other. If you need help in that let me know.
The front Spring towers can sometimes use some straightening up as their Towers can be sagging inward after all these years and or from front or side collision damages found even more so on the V8 Cars but also the Six's that have been worked really hard during their lifetimes. I discovered this way back in the later 1970's on my 1966 Mustang 2 + 2 Fastback that I was working on it would not handle very well. Was the very worse Mustang I ever had of many of them. Turns out looking over the car that it had been hit really hard on the driver’s side at one time. They had replaced all the bolt on suspension parts and the fender on that side but did nothing about the damaged done to the spring tower. After getting that back straight again and doing some extra reinforcement Plates and stich welding this was just like Ford did on the 1969 & 1970 Boss 302 and 429's for Racing use, plus an expert Wheel Alignment that car turned into the very Best Handling Mustang I ever had. If you are interested in hearing more about that let me know.
After that this is where I start rebuilding the front suspensions. A good inexpensive upgrade that you can do yourself is the Roller Spring Shock Mounts. There is an easy way to free up the Upper Control Arms when rebuilding a front suspension. There are also the Full Rollerized Front suspension Parts by Open Tracker too. For those that want to go farther there are the several other front Suspension set ups from TCI using the Mustang II, Pinto Parts, or the Strut type setups using the Fox Chassis Parts.
Back to the stock type setups a Six can use the 1965 / 1966 V8 GT Springs if you want the suspension to be a little stiffer and there is 3/4-inch Front Sway bar that is excellent with an aftermarket 5/8-inch Rear sway bar, or you could also use a 7/8 inch front and a 3/4 inch rear if you want it stiffer yet. For Mustangs without Power Steering a Rollerized Idler Arm really helps a lot when driving at slower speeds and in parking. With all the many improvements in Wheels and Tire Tech an expert Wheel Alignment to the right specs is very important for great Handling. Ask me if you need those specs and or need info on the size of Wheels and tire that can fit these Mustangs many the Alignment shops today don't know how to do this set up right.
For the Front Spindles there are those nice 4 and 5 Lug Disk Brake Set ups made by Scott Drake and some others for use with the stock Six Spindles. There are some advantages though to using the stock Mustang V8 Spindles to with the Better Steering Geometry there is even a stronger Aftermarket Granada spec Big Bearing Spindle with the corrected Geometry for use on the 1965 and 1966 Mustangs. There are also the Dual Piston Disk Brake Kits that are copies of Ford Kelsey Hays Disk Brakes that the early Mustang sued they are very nice.
Chassis upgrades for a Car that will be doing duty on Auto Cross, Road Track and Drag Racing as well as High Performance Street Cars looking for the best in cornering. First with the stock front suspension the best Mod that is almost free is the Shelby / Arning Upper Control Arm Drop. It used to be that there were some free Templets on the net to do this, but they have recently disappeared. I still know how to make my own templet or there are several that can be bought. It’s been written about many times on the site, so I won't put it here unless you want me to. Next is using the Export Brace, fairly reasonable to buy or many are making their own custom ones that can provide some extra clearance for a Multi Carb Intake set up. Monte Carlo Bars used to be made special in a Six Cylinder Spec Bar, but haven seen them lately but wouldn't be too difficult to build one of them. A set of the Sub Frame Connectors is great way to stiffen up the Chassis some, along with a sheet metal plate installed behind the Rear Seat Back sealing off the truck space on the Coupes or Convertibles.
Well that is about the majority of it, I may think of some more yet or if you have other questions let me know.
*I put this in the 144-250 performance section but could belong in Mustang Corral so Mods move where they think appropriate.
