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240 mods update

Moderator: Mod Squad

Blairsville Ed
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240 mods update

Post #1 by Blairsville Ed » Fri Mar 22, 2019 6:54 pm

1968 F100. 240. 3 on the tree. 3.70 rear gear
I’ve been doing mods to my 240 over the last few years with my goal being to get my truck to maintain 60 mph while towing my fishing boat up a long steep grade here in North Georgia.
I started with a basic rebuild of the 240. The bores only needed a light honing, so new rings were installed along with new bearings, gasket and seals. A basic valve job was done and the deck was milled to zero deck. Actually a lit bit beyond zero deck. Compression here at 2000 feet elevation is 150 psi. My fishing boat is about 1200 lbs.

With this set up the best I could maintain was: 40 mph

Added Chevy rockers. 45 mph

Thorough valve job with some port bowl blending,
With .030 over sized intake valves new stock exhaust valves
3 angle valve seat, ground valves with 30 degree back cut. 53mph

Milled the intake manifold carb boss flat and made a
transition plate to mount carb with 45 degree taper
To manifold runners. Carter YF carb 53 mph

Installed Holley 5200 2 barrel carb using a mounting plate
Bolted to the milled intake manifold. 54 mph

Installed efi exhaust manifolds with a Walker Y pipe
And a Walker quiet flow 2-1/2” muffler. 55 mph

Looks like 55 mph is my top.
I thought the efi exhaust would help more.

Max_Effort
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Re: 240 mods update

Post #2 by Max_Effort » Fri Mar 22, 2019 8:52 pm

Good results from the first two mods. I’m impressed by the results from just the higher ratio rockers.

The small improvement from the second two mods suggest that you were already getting enough flow in and out of the engine for the RPM you are running.

What RPM are you pulling the hill at now?

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THE FRENCHTOWN FLYER
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Re: 240 mods update

Post #3 by THE FRENCHTOWN FLYER » Fri Mar 22, 2019 9:49 pm

Nice record keeping. You have a large task at hand.
I base this based on an Econoline van I had with 4 spd OD trans and 3.00 gears. On flat land here in the Midwest it pulled my tandem axle open race car trailer with no problems at highway speeds. One year we towed to Bristol TN for a race. Boy, I took a beating in those surrounding hills, downshifting from 4th to 3rd to 2nd frequently. Not fun. It needed A LOT more torque to climb those hills.
Your 240 will need even more radical mods to keep your speed up. due to its shorter stroke.
FORD 300 INLINE SIX - THE BEST KEPT SECRET IN DRAG RACING

pmuller9
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Re: 240 mods update

Post #4 by pmuller9 » Fri Mar 22, 2019 10:07 pm

You have gone as far as the stock cam will let you.
The EFI exhaust will let you make more power with additional changes but the engine still needs more help pumping air between 2000 and 3000 rpm.
You previously mentioned needing peak torque at 2650 rpm.

If you want to make another big jump in hill climbing mph then it is time for a cam change.

Blairsville Ed
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Re: 240 mods update

Post #5 by Blairsville Ed » Sat Mar 23, 2019 8:50 am

At 55 mph, rpm is around 2425. I think that is were the 240 should be making peak torque. The mods may have shifted the max torque/ rpm point. But.....it’s still only a 240 not a 400.
Rather than going deeper into the engine, I think the gearing would be the easiest solution.
FTF.... did you have the T170 cast iron trans?
I thought about going with that trans with a rear end change to perhaps 4.11.
I think is has a higher ratio 1st gear plus od.


I want to thank all the guys who encouraged me to work with my 240 and all the advice given. Yours years of knowledge are greatly appreciated!!

Max_Effort
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Re: 240 mods update

Post #6 by Max_Effort » Sat Mar 23, 2019 9:56 am

Blairsville Ed wrote:At 55 mph, rpm is around 2425. I think that is were the 240 should be making peak torque. The mods may have shifted the max torque/ rpm point. But.....it’s still only a 240 not a 400.
Rather than going deeper into the engine, I think the gearing would be the easiest solution.
FTF.... did you have the T170 cast iron trans?
I thought about going with that trans with a rear end change to perhaps 4.11.
I think is has a higher ratio 1st gear plus od.


I want to thank all the guys who encouraged me to work with my 240 and all the advice given. Yours years of knowledge are greatly appreciated!!


Just what I thinking about. I’d install an M5OD out of a later truck. They are plentiful, inexpensive and durable. It’s best if you can get the whole setup from a donor truck. Trans, shifter, master cylinder and line. I bought it all with a clutch and flywheel for $100. Then if you want the 4.10 gears, you have more choices for pulling loads and hills, but can keep the RPM down on level ground for economy.

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THE FRENCHTOWN FLYER
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Re: 240 mods update

Post #7 by THE FRENCHTOWN FLYER » Sat Mar 23, 2019 11:05 am

Blairsville Ed wrote:FTF.... did you have the T170 cast iron trans?

I want to thank all the guys who encouraged me to work with my 240 and all the advice given. Yours years of knowledge are greatly appreciated!!


Uh...I think so? It was the one that looked like your typical Top-loader performance 4-speed with an iron case and side rail shifter. In my Econoline Club Wagon it was really funky with that long floor shifter, but fun and good on gas. I think its referred to as the "RUG" code.

It did have a low first but had a big jump between 2nd and 3rd, probably making it very suitable for a light street roadster, but somewhat lacking in a van towing. I think the later M5OD Mazda trans would be better suited, if you don't mind the anguish associated with changing over from a mechanical clutch linkage (which I like for its simplicity, even though it requires occasional adjustment duh!) to the later hydraulic master / slave setup. The M5OD has better gear spacings.
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BigBlue94
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Re: 240 mods update

Post #8 by BigBlue94 » Sat Mar 23, 2019 11:55 am

Before swapping rear gears, find some tires that are about 2" smaller in diameter and mount those up. That will act like you got lower gears installed. However, your mph reading will be off due to the tire swap, so it would be more about your butt-dyno.

I agree that the M5OD-R2 would be a good trans choice, but the zf5 would be even better if you can find one. Theres a 4x2 model at the muncie U-Pull in KC kansas. I saw it 2 days ago. The 4x2 are much easier to find than 4x4. The zf5 has a 5.72 first gear and overdrive, and a good low reverse gear.
1985 Bronco. 309ci I6, NP435, 4.56 gears, Detroit locker and tru-trac, 4" lift, and 37" swamper tires. The 309 is 9.75:1 CR with a Schneider 140H cam, 4bbl, roller rockers, larger valves, and headers.

Blairsville Ed
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Re: 240 mods update

Post #9 by Blairsville Ed » Sat Mar 23, 2019 12:43 pm

Tire size is an interesting idea.
I’m due for tires. I currently have 235/75/15
The 1968 f100 had G78/15 which is equivalent to 215/75r15 or 225/70r15
The 225/70 is about 1.5 inches smaller in diameter than a 235/75

Anybody using these tires sizes on a bump side F100 ?

Max_Effort
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Re: 240 mods update

Post #10 by Max_Effort » Sat Mar 23, 2019 1:10 pm

Blairsville Ed wrote:Tire size is an interesting idea.
I’m due for tires. I currently have 235/75/15
The 1968 f100 had G78/15 which is equivalent to 215/75r15 or 225/70r15
The 225/70 is about 1.5 inches smaller in diameter than a 235/75

Anybody using these tires sizes on a bump side F100 ?


I had that size on short box Chevy square nose. It was a mild hot rod and I wanted it to sit a little lower. They were fine, the handling was better, but a 235/75 LT is better for load capacity.

I would try to borrow some tires just to see if its enough change to help. Unless of course you want a bit lower profile anyway.

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THE FRENCHTOWN FLYER
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Re: 240 mods update

Post #11 by THE FRENCHTOWN FLYER » Sat Mar 23, 2019 1:38 pm

BigBlue94 wrote:Before swapping rear gears, find some tires that are about 2" smaller in diameter and mount those up...

Maybe try some mini-spares?
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Max_Effort
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Re: 240 mods update

Post #12 by Max_Effort » Sat Mar 23, 2019 2:20 pm

Some gear, tire, RPM, MPH, calculators

http://wallaceracing.com/calc-gear-tire-rpm-mph.php

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Shorty
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Re: 240 mods update

Post #13 by Shorty » Sat Mar 23, 2019 3:08 pm

BigBlue94 wrote:Before swapping rear gears, find some tires that are about 2" smaller in diameter and mount those up. That will act like you got lower gears installed. However, your mph reading will be off due to the tire swap, so it would be more about your butt-dyno.

I agree that the M5OD-R2 would be a good trans choice, but the zf5 would be even better if you can find one. Theres a 4x2 model at the muncie U-Pull in KC kansas. I saw it 2 days ago. The 4x2 are much easier to find than 4x4. The zf5 has a 5.72 first gear and overdrive, and a good low reverse gear.


the reverse in the m50d would make for lots of clutch riding to back a trailer. the 4x2 zf5 is a fixed rear yoke rather than the slip yoke of the m5od. When I put the m5od in my 83 to replace the TOD it used the same drive shaft and moved the cross member back a bit. I like the M5OD but I don't use it to tow a trailer and it's pretty flat around here. Rear ratio is 3.55
85 F150 on 78 bronco frame C6 np205 welded dana44 front, trussed posi nine inch rear. EFI exhaust manifolds into one 2 1/2" rolls on 35x12.5x15 Maxxis Trepador.

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Re: 240 mods update

Post #14 by guhfluh » Sun Mar 24, 2019 8:44 pm

THE FRENCHTOWN FLYER wrote:
Blairsville Ed wrote:FTF.... did you have the T170 cast iron trans?

I want to thank all the guys who encouraged me to work with my 240 and all the advice given. Yours years of knowledge are greatly appreciated!!


Uh...I think so? It was the one that looked like your typical Top-loader performance 4-speed with an iron case and side rail shifter. In my Econoline Club Wagon it was really funky with that long floor shifter, but fun and good on gas. I think its referred to as the "RUG" code.

It did have a low first but had a big jump between 2nd and 3rd, probably making it very suitable for a light street roadster, but somewhat lacking in a van towing. I think the later M5OD Mazda trans would be better suited, if you don't mind the anguish associated with changing over from a mechanical clutch linkage (which I like for its simplicity, even though it requires occasional adjustment duh!) to the later hydraulic master / slave setup. The M5OD has better gear spacings.
The T170 and RUG 3spd OD are 2 different transmissions, though the gear spacing is basically the same. 1st and 2nd are decent gearing, but there is a big jump to the 1:1 3rd gear. The TOD/170 is a light duty trans, while the RUG case is supposedly stronger.

If I were towing heavy, I'd opt for the ZF5, but I wouldn't consider a 1500lb boat a heavy load. I'd only want the ZF5 granny low 1st gear for getting the heavy load going. The rest of the time, it is used as a regular 4 spd overdrive trans with larger gear spacing.

I'd much rather the forward gear spread of the M5OD from 1st through 5th during standard driving and small loads, though the reverse gear ratio is a downer for trying to back up at any slow speed.
1967 F-250 Crew Cab 2wd, 300 6cyl, T-170/RTS/TOD 4-speed overdrive
240 head, Offy C, EFI exhaust manifolds, Comp 268H, mandrel 2.5-3" exhaust, Edelbrock 500, Pertronix ignitor and coil, recurved dizzy. 200whp/300wtq

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Re: 240 mods update

Post #15 by sdiesel » Mon Mar 25, 2019 1:34 am

there have been cases where, a transfer case has been used with a 2wd vehicle, only for the low range it offers for just such a need.
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my lastest and final fling is a fresh 300 in an 88 ford f350 dually 4X flatbed

Blairsville Ed
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Re: 240 mods update

Post #16 by Blairsville Ed » Mon Mar 25, 2019 8:28 am

This process has been fun to see what each mod does. In reality, the few times a year that I towed the fishing boat doesn’t justify expensive upgrades, however the mods suggested on this site have been relatively inexpensive and have helped.
The 1968 f100 will now be towing our 3200 lb. pontoon boat. It’s only 2 miles of flat roads to the launch but pulling that boat up the launch ramp is a challenge for the 240, And, I want to keep the 3 on the column shifter. I’m nostalgic.
I’ve considered the early Bronco transfer case because it is a direct bolt on 2 speed unit.
I’m now considering the cast iron rug trans. It has a lower ratio 1 st gear and I could go with smaller tires. I need tires anyway.
And, I’m planning on installing a traction loc set up for the rear axle. I could re-gear at that time.
It’s hard to calculate the torque increase with gearing and tire changes especially the grunt needed to pull a 3200 lb boat up a launch ramp.
Decision, decision.....

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THE FRENCHTOWN FLYER
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Re: 240 mods update

Post #17 by THE FRENCHTOWN FLYER » Mon Mar 25, 2019 9:35 am

After watching a few youtube "boat ramp FAILS" I'd add a receiver and ball to your front bumper so a mate can tether your truck as you back into the ramp. It's also useful for moving the boat around the yard in tight places.Don't forget to add a tall vent tube to the transfer case or trans so you don't ingest water.
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guhfluh
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Re: 240 mods update

Post #18 by guhfluh » Mon Mar 25, 2019 10:41 am

Blairsville Ed wrote:This process has been fun to see what each mod does. In reality, the few times a year that I towed the fishing boat doesn’t justify expensive upgrades, however the mods suggested on this site have been relatively inexpensive and have helped.
The 1968 f100 will now be towing our 3200 lb. pontoon boat. It’s only 2 miles of flat roads to the launch but pulling that boat up the launch ramp is a challenge for the 240, And, I want to keep the 3 on the column shifter. I’m nostalgic.
I’ve considered the early Bronco transfer case because it is a direct bolt on 2 speed unit.
I’m now considering the cast iron rug trans. It has a lower ratio 1 st gear and I could go with smaller tires. I need tires anyway.
And, I’m planning on installing a traction loc set up for the rear axle. I could re-gear at that time.
It’s hard to calculate the torque increase with gearing and tire changes especially the grunt needed to pull a 3200 lb boat up a launch ramp.
Decision, decision.....
I don't know that there is any column shift linkage that works with the RUG?
1967 F-250 Crew Cab 2wd, 300 6cyl, T-170/RTS/TOD 4-speed overdrive
240 head, Offy C, EFI exhaust manifolds, Comp 268H, mandrel 2.5-3" exhaust, Edelbrock 500, Pertronix ignitor and coil, recurved dizzy. 200whp/300wtq

Blairsville Ed
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Re: 240 mods update

Post #19 by Blairsville Ed » Mon Mar 25, 2019 11:05 am

The you tube videos are sobering.
I use a large wheel chock tied to my bumper and it’s a good launch that I have here.
I did a practice run with the truck and boat at the launch. The 240 got it up the ramp but I had to ride the clutch and then one tire started to spin. Trac loc posi will be put in eventually.

The column shift with the rug trans is possible. It has to be the cast iron trans with the side shifter levers.
Reverse has its own lever so the column would shift 1-2 and 3-4.
I would have to rig up a cable type system to engage reverse with the column shift in neutral.

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Re: 240 mods update

Post #20 by THE FRENCHTOWN FLYER » Mon Mar 25, 2019 11:50 am

Blairsville Ed wrote:The column shift with the rug trans is possible. It has to be the cast iron trans with the side shifter levers.
Reverse has its own lever so the column would shift 1-2 and 3-4.
I would have to rig up a cable type system to engage reverse with the column shift in neutral.

That would be a fun project and one that would have purists scratching their heads trying to figure out how you got a four speed OD to work. A Morse cable could work, or maybe re-purposing the E-brake handle.

Early Saab 3-cyl 2-stroke sedans had a four speed column shifted trans. My wife drove one in high school.
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Blairsville Ed
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Re: 240 mods update

Post #21 by Blairsville Ed » Mon Mar 25, 2019 1:29 pm

I’m working on finding that particular transmission.

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Re: 240 mods update

Post #22 by Lazy JW » Tue Mar 26, 2019 12:27 pm

Blairsville Ed wrote:... planning on installing a traction loc set up for the rear axle. I could re-gear at that time...


Stock size tires and a set of 4.56 gears will get you to your goal :nod: :thumbup: A planetary overdrive would be oh-so-very sweet :D
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Blairsville Ed
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Re: 240 mods update

Post #23 by Blairsville Ed » Wed Mar 27, 2019 7:49 pm

I looked at a Toploader overdrive transmission today.
I noticed that it’s a slip yoke style. My current 3 speed is a fixed yoke with a 2 piece driveshaft, long bed truck
How do I Adapt the driveshaft from a fixed yoke to a slip yoke ?

guhfluh
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Re: 240 mods update

Post #24 by guhfluh » Fri Mar 29, 2019 9:14 pm

No real adaptation required with a 2 piece. Bolt the slip yoke to the u-joint. I had my front shafts shortened, but shouldn't have. I measured wrong and had it cut down before the trans was installed. I would have been better leaving it.
1967 F-250 Crew Cab 2wd, 300 6cyl, T-170/RTS/TOD 4-speed overdrive
240 head, Offy C, EFI exhaust manifolds, Comp 268H, mandrel 2.5-3" exhaust, Edelbrock 500, Pertronix ignitor and coil, recurved dizzy. 200whp/300wtq

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