Good day

I drive a 1977 F250 with the 351M engine, C6 transmission and Dana 60 rear axle. I would like to lower the engine speed a little at 75mph. Are there other options besides installing a gear vendor? I saw there is a Ford E4OD transmission. Would this fit my engine?
Thank you very much.

Tobias

 

An E4OD from a 460 will physically bolt to your 351M block although I am not sure of what flexplate you would need to have the correct fitment of the torque converter and starter.

Keep in mind that the transmission is longer than a C6 so the driveshaft between the transmission and transfer case (if it's a "highboy") will need to be shortened significantly....which is the best case because if it's not really a "highboy" (later 77 with married transmission/transfter case) then the front drivehaft gets longer (expensive) and the rear driveshaft gets shorter. If it's 2WD, then it'll just be the rear driveshaft, obviously. Transmission crossmember location will have to be changed in any case.

A bigger hurdle is that the "E" in E4OD means "electronically controlled" so there is the added complexity/cost of an aftermarket controller and the speed/position sensors required to make that function.

 

The GV is more than just an over drive. if you have an automatic you get a 6 speed, if you have a 4spd you get a 7 speed.

 

Thank you for the answer, I didn't know about the electronic control.
sounds like too much effort.

 

Yes, I am aware of that. I also think this is a good solution.
But the transport to Germany is too expensive for me.

 

Hi Tobias, can't help you with your question, but where in Germany are you located? I'm from Bavaria.

 

Hi, I'm located near Mannheim ( Baden-Württemberg)

 

You can find an E4OD and the needed parts in Germany?

 

I saw one in the junkyard in Holland and the idea of ​​an upgrade came to me, but I didn't know about electronic controls

 

Is 75 mph a must? What rear gearing is in it now, 3.54 or 4.10 or ?.?? Taller tires and/or more air will lower rpms some.

 

IT is a 3,54 install.
I will try more air in the tires

 

Air won't really make any difference on gearing. the circumference of the tire is what matters and that doesn't change.

All things considered if you really want an OD the GV is probably the best option for you. everything you need in 1 box. but you're right it's not cheap.

I put a GV in my highboy , 4.10 gears and 33" tires. it's like a completely different vehicle now, just purrs down the road instead of screaming. but that's the value in an OD, you'll never save enough fuel to pay for it so don't go there.

 

Yes, I think so, too.
This will not be worth the transport costs and customs

 

Agreed, it might not be huge, it likely would not be enough to suit, but it will make a difference as it increases rolling diameter ... and as a side note, reduces rubber scrubbing the road in the compressed contact patch, thus reducing resistance and tire wear. Might be a harsh ride though. Just do not go up psi over maximum inflation for the tire by much. 3-4 psi over is likely OK, 20 psi over is dang dangerous.

Going from 4.10s to 3.54s is like a 15% OD right there. My truck's 3.50 is like a 17% OD compared to 4.10s ...but it's close to a 3.54.
My truck with its 3.50 gear and 31" tires with C-6 is at about 2400 at 55 mph and about 3272 at 75 mph.
If I only changed to 33" tires, my rpm would drop to more like 2250 rpm at 55 mph and about 3070 at 75 mph.

If I swapped up to 4.10s from my 3.50s, that would be a 17% increase in rpm at any given speed.

My truck if fitted with a 4.10 gear and 31" tires with C-6 would see about 2811 at 55 mph and about 3830 at 75 mph.
If I then changed to 33" tires, my rpm would drop to more like 2120 rpm at 55 mph and about 3890 at 75 mph.

If OP has 3.54 gearing, not too many great options remain to lower rpms at 75 short of swapping his whole rear (9" with 3.00 or 2.75 gear?) or the GV OD other than taller tires. I never looked to see if there were controllers to add to shift an E4OD trans. Why I asked if 75 mph was a must?

I have a few old magazines, PM, PS, etc ..... and guys once upon a time used an old Rambler's 3 speed transmission mounted "reversed" to provide a big OD in 2nd, or straight in 3rd. Let that jalopy really step out on that new fangled interstate highway.

I had all those figures in a file, I once considered 4.10s as a swap, but was gonna need really tall tires to suit me, like 35 or 36" tall. I and my old truck seem happiest together if we just keep it under 63 or so mph.

 

So you know the $$ to get the GV to your door and say it is too much.

What is the cost of the E4OD to get it to your door and then the computer to make it work to your door?

Forget about the drive shaft as both would need a drive shaft mod.

As for the starter & converter fitment.
Will his starter now bolt to the E4OD trans bolt pattern?
If so then I see using the starter and flex plate he has now and if the converter will not bolt up have it drilled for the E4OD converter..

If the starter bolt pattern is different then he would need to use the E4OD starter.
He would then need to check the bendix throw of the old & new starter if the same and the gear tooth could if it could be used with his old flex plate.
I say old flex plate as I believe the plates are balanced for the size motors but if the E4OD plate will bolt to the motor and match the E4OD starter he could have it match balanced to the old plate.Oh he would also need to measure from the block bell housing face to the flex plate gear of both plates for the bendix throw.
I do think this this could be worked out once you have all the parts in front of you from the E4OD (plate / starter / transmission and drive shaft yoke at transmission.
Dave ----