I have a 68/75 mix and was looking for a new carb. Car is under restoration but with a little starting fluid it did start / run. Pony carbs seemed taken back by this block and head combination and advised I get the head straightened out before I get a carb. Is this setup OK the way it is ? or do I tear it down and rebuild ? Where can I get a carb for this setup ?
Mixing 68 Block with 75 head
- Thread starter blaze65
- Start date
Howdy Blaze:
And welcome to THE FORUM!
The first question is what carb is on the engine now?
The '75 head would have had a Carter YF carburetor, which had a cable throttle linkage system and was designed to work with a Non-Load-O-Matic distributor. Since you have a '68 block is that also the distributor you are using? If so, the Carter YF will work just fine if in good condition and good tune.
If you're going to be dealing with Pony Carb, specify that you want a Carter YF for a '75 engine. IF you tell them any more details they will get very anal and confused.
Are you really restoring this car to OEM original? Or just updating and refreshing it?
Give us more details.
Adios, David
And welcome to THE FORUM!
The first question is what carb is on the engine now?
The '75 head would have had a Carter YF carburetor, which had a cable throttle linkage system and was designed to work with a Non-Load-O-Matic distributor. Since you have a '68 block is that also the distributor you are using? If so, the Carter YF will work just fine if in good condition and good tune.
If you're going to be dealing with Pony Carb, specify that you want a Carter YF for a '75 engine. IF you tell them any more details they will get very anal and confused.
Are you really restoring this car to OEM original? Or just updating and refreshing it?
Give us more details.
Adios, David
Thanks for the Welcome, and for the help. What is on the Car now is (I believe) an autolite 1100. The Tag is off the carb but it certainly looks like a 1100 from what I can see off the net. It is also for an automatic car. It has a dashpot with the two diaphrams. It also has several holes plugged up which I am not sure of. I assume some of these are throttle kickdown from the automatice, probably the correct vacuum port, etc. As far as the Distributor I am not sure. It only has a single vacuum line on it coming from what looks like the adapter plate below the carb. I thought Pony Carbs told me a loadomatic had two lines but I am not sure.
The car will not be an OEM car. It's a 65 T code convertible and I have replaced just about every piece of sheet metal on the car, along with patching the torque boxes, trunk dropoffs, etc. My plan is to replace the rear and the front to be able to carry 5 lugs.
The goal with the engine is if it works as is I would keep it as is but when Pony carbs said the head needed straigtened out I was concerned. It won't be an oem car but I want it to run as best it can. . Thanks again
The car will not be an OEM car. It's a 65 T code convertible and I have replaced just about every piece of sheet metal on the car, along with patching the torque boxes, trunk dropoffs, etc. My plan is to replace the rear and the front to be able to carry 5 lugs.
The goal with the engine is if it works as is I would keep it as is but when Pony carbs said the head needed straigtened out I was concerned. It won't be an oem car but I want it to run as best it can. . Thanks again
If everything is stock (which is a big if this late in the game) what will he end up with for a compression ratio with that combo?
I have a 62cc head and would have ended up with something like 6:1 compression with my bottom end. Theory is I have non typical pistons. I had to rework my original head to get up to around 8.25 :1.
I have a 62cc head and would have ended up with something like 6:1 compression with my bottom end. Theory is I have non typical pistons. I had to rework my original head to get up to around 8.25 :1.
65andonly18
Well-known member
Does anyone have a pic of a non load o and a load o, because i only have one line coming off my dizzy as well does that mean its a non load? Thanks
Eric Rose
Famous Member
Pony Carbs is going to steer you in the direction of having everything stock and numbers-matching. Since they are in the business of supplying carbs for restorations and upgrades to stock setups thats the sort of advice they give.
If your goal is working with what you have (like most of us here on the forum) its probably best to find out what parts you need on your own (the guys here are super knowledgeable) and then order them from Pony.
The '70's heads have much bigger chambers, and the new composite headgaskets are thicker than they were back then. So like Fordconvert said there's a chance you have really low compression, unless whoever put your motor together had the sense to mill the head to make up for the lost compression. I'd say start with a compression test and see what your cylinder pressure numbers are.
The '70's heads are more desirable IMO because they have the bigger carb opening and the bigger volume intake log. The Carter YF they used is a pretty decent carb.
Heres a picture of a Carter YF and the cable throttle that goes with it.
Another carb from the '70's engines was the Holley 1946. It used the same cable throttle as the YF:
Neither of these carbs use vacuum for the kickdown, they had a lever that would trip then the linkage was at full throttle. The holes that were plugged up are probably for a modulator valve (automatic) and smog stuff. I know the 1946 of mine had a lot of smog stuff on it (and thats why I junked it).
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If your goal is working with what you have (like most of us here on the forum) its probably best to find out what parts you need on your own (the guys here are super knowledgeable) and then order them from Pony.
The '70's heads have much bigger chambers, and the new composite headgaskets are thicker than they were back then. So like Fordconvert said there's a chance you have really low compression, unless whoever put your motor together had the sense to mill the head to make up for the lost compression. I'd say start with a compression test and see what your cylinder pressure numbers are.
The '70's heads are more desirable IMO because they have the bigger carb opening and the bigger volume intake log. The Carter YF they used is a pretty decent carb.
Heres a picture of a Carter YF and the cable throttle that goes with it.
Another carb from the '70's engines was the Holley 1946. It used the same cable throttle as the YF:
Neither of these carbs use vacuum for the kickdown, they had a lever that would trip then the linkage was at full throttle. The holes that were plugged up are probably for a modulator valve (automatic) and smog stuff. I know the 1946 of mine had a lot of smog stuff on it (and thats why I junked it).
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Howdy back Blaze and All:
The Load-O-Matic (LoM) distributor is easy to ID. And it does only have one vacuum line from the carb. If you remove the distributor cap you will see two springs fairly close together near the six o'clock position. To operate as designed the carb will have a Spark Control Valve, which sends a specifically modified load sensitive vacuum signal to the distributor. There is a sticky at the top of this forum describing the function of the SCV and the LoM distributors function.
A '75 distributor could have been the last of the point type, with both vacuum and centrifugal advance, or the 1st generation of the Dura Spark, pointless distributors. Many of the early '70s points distributors had both vacuum advance and a vacuum retard function, which had two vacuum lines to the distributor vacuum cannister.
Do you know the history of how this '75 head came to be on your '68 block? There are several issues that will effect the engines compression ratio. When the head was changed, what head gasket was used. The factory put it together, both is '68 & '75, with a .025" steel shim gasket, which are no longer easily available. Replacement gaskets measure about .050" thick. The other issue is the increased volume of the later combustion chambers. The '75 head will measure 62 ccs as compared to 52cc for the '68 head. Finally, when a head is swapped it is usually given a valve job which may have included a mill cut to true the mating surfaces. If this was done, how much was removed? Short of knowing the history, until the head is removed and the chambers measured, it is only guessing.
Assuming a chamber size of 62 ccs, a gasket thickness of .050", and stock 48 state dished pistons, your CR will be about 7.6:1. Stock, a '68 200 was rated at 8.8:1.
Now, back to your carb situation. From your discription of the two dashpots (Only one is a dashpot, the other is the accelerator pump) It sounds like an 1100. Is there a SCV? 1st, verify what carb you have. Is it compatible with the distributor? What type of linkage are you using?
If you already have a '65 shop manual, and you should given the work you've already done, look up the carb section and compare visually.
Keep the info coming.
Adios, David
The Load-O-Matic (LoM) distributor is easy to ID. And it does only have one vacuum line from the carb. If you remove the distributor cap you will see two springs fairly close together near the six o'clock position. To operate as designed the carb will have a Spark Control Valve, which sends a specifically modified load sensitive vacuum signal to the distributor. There is a sticky at the top of this forum describing the function of the SCV and the LoM distributors function.
A '75 distributor could have been the last of the point type, with both vacuum and centrifugal advance, or the 1st generation of the Dura Spark, pointless distributors. Many of the early '70s points distributors had both vacuum advance and a vacuum retard function, which had two vacuum lines to the distributor vacuum cannister.
Do you know the history of how this '75 head came to be on your '68 block? There are several issues that will effect the engines compression ratio. When the head was changed, what head gasket was used. The factory put it together, both is '68 & '75, with a .025" steel shim gasket, which are no longer easily available. Replacement gaskets measure about .050" thick. The other issue is the increased volume of the later combustion chambers. The '75 head will measure 62 ccs as compared to 52cc for the '68 head. Finally, when a head is swapped it is usually given a valve job which may have included a mill cut to true the mating surfaces. If this was done, how much was removed? Short of knowing the history, until the head is removed and the chambers measured, it is only guessing.
Assuming a chamber size of 62 ccs, a gasket thickness of .050", and stock 48 state dished pistons, your CR will be about 7.6:1. Stock, a '68 200 was rated at 8.8:1.
Now, back to your carb situation. From your discription of the two dashpots (Only one is a dashpot, the other is the accelerator pump) It sounds like an 1100. Is there a SCV? 1st, verify what carb you have. Is it compatible with the distributor? What type of linkage are you using?
If you already have a '65 shop manual, and you should given the work you've already done, look up the carb section and compare visually.
Keep the info coming.
Adios, David
First to David, Eric and all, first and foremost, many many thanks. I am not a mechanic and I have been lost trying to figure out what I have and what to do. Again thanks for your help and advice. You have all been very helpful.
Regarding the 75 head I don't know how it ended up on this 68 block. The car was a rustang Flintstone mobile with a rotted cnv top and 6 inches of leaves in it when I got it. With the car came 2 additional motors another 6 and a 289. I never picked up the other engines as I have no room for them but I assume the other 6 was the original. I have a picture of the carb but can't upload it. Best I can describe it looking from the passenger side. The 1100 sits on top of what looks like an adapter plate on the log. Fuel line in the front and almost immed. below the dashpot the hose from the PCV connects to what looks like a port on the adapter plate. Looking at the carb directly from the side there is another hole in this same adapter plate. It has a screw with a rubber plug in it and nothing else. Directly above that plug is the bolt that holds the carb down and immediately above that is a whole/port on the carb. This is also plugged with a fitting / screw. I assume this was/is a vacuum port. Directly to the left of this whole is a SCV. Further back is the choke which also has an empty port with I assume some takes heat from the manifold but I don't know how as there is no tube there. Vacuum to the Dist is coming from a rectangular box shaped fitting that looks to tap directly into the log. Lastly in front of the engine near the heater hose connection is a 3 prong fitting. There are no hoses / tubes on it.
The good news is the car does start or at least she did on starting flluid and a new condensor and set of points. I get more info on the Dist this weekend when I work on it. I am OK with replacing the dist with something electronic if that is advisable but not sure what to do with the carb. I have bought an 1100 rebuild kit as when I put gas in the car it just leak out all over the manifold. I assume all the gaskets are shot but I have not tried to rebuild it yet. Any thoughts welcome.
Dave - Will be getting the book shortly. Thanks again
Regarding the 75 head I don't know how it ended up on this 68 block. The car was a rustang Flintstone mobile with a rotted cnv top and 6 inches of leaves in it when I got it. With the car came 2 additional motors another 6 and a 289. I never picked up the other engines as I have no room for them but I assume the other 6 was the original. I have a picture of the carb but can't upload it. Best I can describe it looking from the passenger side. The 1100 sits on top of what looks like an adapter plate on the log. Fuel line in the front and almost immed. below the dashpot the hose from the PCV connects to what looks like a port on the adapter plate. Looking at the carb directly from the side there is another hole in this same adapter plate. It has a screw with a rubber plug in it and nothing else. Directly above that plug is the bolt that holds the carb down and immediately above that is a whole/port on the carb. This is also plugged with a fitting / screw. I assume this was/is a vacuum port. Directly to the left of this whole is a SCV. Further back is the choke which also has an empty port with I assume some takes heat from the manifold but I don't know how as there is no tube there. Vacuum to the Dist is coming from a rectangular box shaped fitting that looks to tap directly into the log. Lastly in front of the engine near the heater hose connection is a 3 prong fitting. There are no hoses / tubes on it.
The good news is the car does start or at least she did on starting flluid and a new condensor and set of points. I get more info on the Dist this weekend when I work on it. I am OK with replacing the dist with something electronic if that is advisable but not sure what to do with the carb. I have bought an 1100 rebuild kit as when I put gas in the car it just leak out all over the manifold. I assume all the gaskets are shot but I have not tried to rebuild it yet. Any thoughts welcome.
Dave - Will be getting the book shortly. Thanks again
Eric Rose
Famous Member
Work with the points stuff now to get it running, thats what I did with mine. Once the engine actually runs you'll see if there are any major problems to deal with.
I don't recall if you said your '68 block was a 200 or a 170. The easy way to tell is to count the freeze plugs on the side of the block under the exhaust manifold. A 170 will have 3 and a 200 will have 5. On the 200 on of the plugs will be behind the starter and you have to feel for it.
The DSII will fit the 200 blocks just fine. The 170 blocks require a little work but people on this forum have done it.
Theres a DSII thread that stays at the top of the forum.
The tube on the choke housing goes to a hole tapped into the exhaust manifold. It just puts exhaust onto the choke coil to warm it up. The "box shaped fitting" is a vacuum manifold. I had my distributor advance running there too at one time , right now my transmission modulator is connected there. The 3 pronged fitting on the thermostat housing is a temperature control switch for the smog gear from the '75 motor.
I don't recall if you said your '68 block was a 200 or a 170. The easy way to tell is to count the freeze plugs on the side of the block under the exhaust manifold. A 170 will have 3 and a 200 will have 5. On the 200 on of the plugs will be behind the starter and you have to feel for it.
The DSII will fit the 200 blocks just fine. The 170 blocks require a little work but people on this forum have done it.
Theres a DSII thread that stays at the top of the forum.
The tube on the choke housing goes to a hole tapped into the exhaust manifold. It just puts exhaust onto the choke coil to warm it up. The "box shaped fitting" is a vacuum manifold. I had my distributor advance running there too at one time , right now my transmission modulator is connected there. The 3 pronged fitting on the thermostat housing is a temperature control switch for the smog gear from the '75 motor.
The tube is not supposed to have exhaust in it. Its supposed to draw air through a tube cast into the exhaust manifold there fore heating the air. If you have exhaust coming out that tube you have a cracked manifold and likely a really plugged up carb.
Looks like some tiny cracks, no big deal, I can live with them for a while right?
Looks like some tiny cracks, no big deal, I can live with them for a while right?
Thanks again. I can't tell you how happy to have this forum and all of your help.
I believe it is a 200 based on the block number C8DE-6015. I'll check out the distributor and post the info.
What is the whole in the adapter plate with screw/plug, throttle kickdown for an auto trans ??, is the port to the right of the SCV (that is also plugged) the vacuum port ? Why is it plugged and are they taking vacuum from the intake ?, is it OK take vacuum from anywhere , or did it matter based on the intake/carb/head ?
I believe it is a 200 based on the block number C8DE-6015. I'll check out the distributor and post the info.
What is the whole in the adapter plate with screw/plug, throttle kickdown for an auto trans ??, is the port to the right of the SCV (that is also plugged) the vacuum port ? Why is it plugged and are they taking vacuum from the intake ?, is it OK take vacuum from anywhere , or did it matter based on the intake/carb/head ?
Howdy back Blaze and all:
The C8DE block casting code was used on both 170s and 200 blocks. Count the freeze plugs to be sure on which you have.
Depending on which adapter plate your engine has, the hole could be a tap for a post for the carb linkage to pivot on. This would be an indication that the adapter was from a '64 to '68 200 using an 1100 carb. This type adapter plate was never used on a '75 engine.
On an 1100 the port to the right of the SCV is the port for the vacuum line to the distributor. Originally the line was a metal line with a screwed in fitting both at the carb and the distributor.
If they were taking vacuum from the manifold, it is not correct as designed. Will it work? to some extent, but not well.
THe LoM distributor relies on the modified vacuum signal from the SCV to operate as designed. It sounds like you will need to thoroughly rebuild and refresh both the distributor and the carburetor to get it running good.
The hot air drawn through the exhaust manifold is unfiltered air. Not one of Fords better ideas. The hot air sucked in caused the bimetal coiled spring in the choke housing to open the choke.
Thanks for buying our Handbook, but I'd encourage you to invest in a shop manual as well. It will be much more detailed.
Keep the info coming.
Adios, David
The C8DE block casting code was used on both 170s and 200 blocks. Count the freeze plugs to be sure on which you have.
Depending on which adapter plate your engine has, the hole could be a tap for a post for the carb linkage to pivot on. This would be an indication that the adapter was from a '64 to '68 200 using an 1100 carb. This type adapter plate was never used on a '75 engine.
On an 1100 the port to the right of the SCV is the port for the vacuum line to the distributor. Originally the line was a metal line with a screwed in fitting both at the carb and the distributor.
If they were taking vacuum from the manifold, it is not correct as designed. Will it work? to some extent, but not well.
THe LoM distributor relies on the modified vacuum signal from the SCV to operate as designed. It sounds like you will need to thoroughly rebuild and refresh both the distributor and the carburetor to get it running good.
The hot air drawn through the exhaust manifold is unfiltered air. Not one of Fords better ideas. The hot air sucked in caused the bimetal coiled spring in the choke housing to open the choke.
Thanks for buying our Handbook, but I'd encourage you to invest in a shop manual as well. It will be much more detailed.
Keep the info coming.
Adios, David
I am hopful I have inserted this picture correctly. This is the Carb on top of my engine. ALl of the plugged up ports I mentioned are visible.
What do you think ?, Trash this carb ?? Rebuild it ?? Replace it with what ?
I will check the Dist out and let you know what it looks like.
What do you think ?, Trash this carb ?? Rebuild it ?? Replace it with what ?
I will check the Dist out and let you know what it looks like.
Eric Rose
Famous Member
Yeah, it makes sense that they would just run a tube into the manifold to heat the choke instead of using the actual exhaust. D'oh.
Maybe the reason the distributor is plugged in to a manifold vac. source is that it is a dual advance and not compatible with the SCV?
What might be a good idea is to do a cleaning/rebuild of the carb, set the points and see what you can get it to do. Start with a timing light with the vacuum to the distributor disconnected to set the initial timing. Factory timing is 8 degrees if I remember right and thats a good starting point. Most of us are running 12. Then maybe you can rev it up and see if you can see if the timing advances to see if it has any centrifugal advance before you connect the vacuum back up. If you don't have centrifugal advance you either have a dual advance thats seized or a LOM.
Upgrading to the electronic ignition is something I highly recommend if you aren't worried about keeping it 100% original. Its a lot easier to set it and forget it than it is to set points every couple of months, and you get added performance and the ability to add upgrades later like a hotter coil or an MSD box. 8)
Maybe the reason the distributor is plugged in to a manifold vac. source is that it is a dual advance and not compatible with the SCV?
What might be a good idea is to do a cleaning/rebuild of the carb, set the points and see what you can get it to do. Start with a timing light with the vacuum to the distributor disconnected to set the initial timing. Factory timing is 8 degrees if I remember right and thats a good starting point. Most of us are running 12. Then maybe you can rev it up and see if you can see if the timing advances to see if it has any centrifugal advance before you connect the vacuum back up. If you don't have centrifugal advance you either have a dual advance thats seized or a LOM.
Upgrading to the electronic ignition is something I highly recommend if you aren't worried about keeping it 100% original. Its a lot easier to set it and forget it than it is to set points every couple of months, and you get added performance and the ability to add upgrades later like a hotter coil or an MSD box. 8)
Thats an 1100. The tube off the adapter plate looks to be EGR. That black 90* fitting pointing to the choke is the scv port and the thing its partially covering is the scv itself. I have never seen one that looked like that before, all I have and have seen are a fitting for a steel line.
The egr tube is about 6 o clock in the photo and is partially covered by the cross brace. The PCV should be the hose in the 4 o clock position under the deceleration pot on the carb.
Howdy back Blaze and All:
You've gotten good info on all the hoses and plugs. But, I'm curious. Is the big hose going over the valve cover going to the distributor vacuum cannister?
The next step in analysing this combination will be to determine which distributor you have, for certian. With that information we can help you to identify your options. No Ford production distributor was ever built to use full manifold vacuum. The only time you may want to use manifold vacuum is with a performance cam.
On the carb, the tap with the "L", next to the SCV is the source for a LoM distributor. The heavy hose coming out of the carb adapter should go to a PCV in the top of the valve cover.
The only other you'll need to make the choke function correctly is the threaded male end on the choke housing. You will need a metal piece of tubing bent down near the exhaust manifold. Does your current exhaust manifold have about a 1/4" hole centered near the top of it. If it does, that is where the metal tube should be inserted. What is the casting code on the exhaust manifold?
Your homework-
*Count freeze plugs
*determine what distributor you have.
Your next descision/discussion will be- do you want to stay with what you have, or upgrade to a later, more efficient combo. The Dura Spark pointless distributor Eric suggests will do it's best when paired with a Carb that has a true ported vacuum source for the vacuum advance. So, stay with the Autolite 1100 carb and LoM distributor and rebuild and refresh, or upgrade to a DS II and later carb, either an 1101 from a '69 Mustang with a 250 or a Carter YF. The former is stock/restore, the later is restomod- fairly stock, but upgraded for economy, reliability and performance.
Don't you love an adventure?
Keep the info coming.
Adios, David
You've gotten good info on all the hoses and plugs. But, I'm curious. Is the big hose going over the valve cover going to the distributor vacuum cannister?
The next step in analysing this combination will be to determine which distributor you have, for certian. With that information we can help you to identify your options. No Ford production distributor was ever built to use full manifold vacuum. The only time you may want to use manifold vacuum is with a performance cam.
On the carb, the tap with the "L", next to the SCV is the source for a LoM distributor. The heavy hose coming out of the carb adapter should go to a PCV in the top of the valve cover.
The only other you'll need to make the choke function correctly is the threaded male end on the choke housing. You will need a metal piece of tubing bent down near the exhaust manifold. Does your current exhaust manifold have about a 1/4" hole centered near the top of it. If it does, that is where the metal tube should be inserted. What is the casting code on the exhaust manifold?
Your homework-
*Count freeze plugs
*determine what distributor you have.
Your next descision/discussion will be- do you want to stay with what you have, or upgrade to a later, more efficient combo. The Dura Spark pointless distributor Eric suggests will do it's best when paired with a Carb that has a true ported vacuum source for the vacuum advance. So, stay with the Autolite 1100 carb and LoM distributor and rebuild and refresh, or upgrade to a DS II and later carb, either an 1101 from a '69 Mustang with a 250 or a Carter YF. The former is stock/restore, the later is restomod- fairly stock, but upgraded for economy, reliability and performance.
Don't you love an adventure?
Keep the info coming.
Adios, David
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