C4 to torque tube

[whizzernick]

I am planing a flathead power to C4 automatic and would like to use original torque tube . Also any way to use 32-28 eng with C4 ? I have the speedway
Kit . But it only works with 49-53 eng.

[Dick]

You might try this place. he may have some answers for you.
his bellhousing is smaller but requires special torque converter
Gene: 5zero3 364-2934 (Oregon)
https://www.flat-o.com/carproducts/flatomatic.htm

[Ol' Ron]

Upgrading to an auyomatic transmission is a good improvement to a street rod. However this requires a major modifications to the frame. (Pre 49). another question, why the C4? exelent trans, ran one behind a stock Merc engine in my truck. A better choice whould have been an AOD.. Now, why Keep the stock rear? This is the weak link in a very expensive modification to the car/truck. I'd recommend a Spicer 35 from a Jeep Grand cherokee with 3.73 gears and posi. Very inexpensive amd neglected by most as , not strong enough.. Remember we're running a flathead not an LS.
Gramps.

[Ronnieroadster]

Originally Posted by whizzernick

I am planing a flathead power to C4 automatic and would like to use original torque tube . Also any way to use 32-28 eng with C4 ? I have the speedway
Kit . But it only works with 49-53 eng.

To put the C-4 behind anything prior to 49 use the Flatomatic conversion that Dick wrote above. The Speedway conversion as you found out will not work for anything prior to 8BA era.

Now the idea of putting the C-4 to a torque tube would be extremely difficult to accomplish. First issue is the transmission length the shortest C-4 was used in vans however they are hard to find and even that C-4 is still to long.

The next issue would be getting the transmission connected to the torque tube the C-4 yoke is a fine spline into the tranny the U yoke needed from that
point to the torque tube driveshaft is 6 or 10 spline anything like that would be a one off custom made part. Certainly not impossible to have made but also not a simple item to make.

Then there's the bell flange needed on the transmission to connect to the rear. Somehow the rear of the C-4 needs to be modified to accept this arrangement that's going to be extremely difficult to accomplish.

And then there's the question would the C-4 aluminum case be able to handle the load placed upon it from the torque tube since that's what places and keeps the rear axle assembly in place. The pushing load on the aluminum case may cause cracking.

The C-4 is an outstanding transmission behind the flathead combined with a rear gear in the 280 to 290 range its dam near perfect . I've been involved in a number of flatheads converted to the C-4 based off the flatomatic design and the ford 8 inch rears or quick-change rears.
Ronnieroadster

[rotorwrench]

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Automatics use the Yoke as the seal surface and generally have a bushing in there to keep it stable. If a person does away with all that then the tail housing would require extensive modification (similar to early Lincoln overdrive transmission set ups) and even after that there has to be a way to keep ATF from getting into the U-joint housing. There would be a lot of engineering involved with s setup like this.

The other method is to have a fabricated cross member that supports just the torque tube front ball and cap parts with the transmission driving into that with a standard U-joint connected to the driveshaft. The torque tube & shaft would likely still need to be shortened even with the shortest C4 you can find. This link to the HAMB has a photo from Pete about half way down the page.
https://www.jalopyjournal.com/forum/...-3spd.1154845/