C4- torque converter- flywheel

Does the year of the trans make a difference as to what size the torque converter and flywheel are? For instance, my trans is a '66. I tried to place the valve body in another c4. It wouldn't fit. Then I found 69 and earlier were different than 70 and up. my trans and the other had different input shafts. Mine was a bit smaller (24 Spline probably) Does the spline count correlate to the flywheel size 157 or 164? Any help is great. I'm just trying to figure out if I will need to get a different flywheel if I use this other trans.

 

From what I know the spline count is based on the year of the trans. Pre 69 have a different spline count than the 70 and up thus the torque converters are different. I understood that the 164 tooth flywheel were for the heavy duty c4 trans that have the larger bellhousing and torque converter. If you have the smaller flywheel it will work with pre and post 69 standard c4 trans. The heavy duty c4 has a different case and bellhousing and was used in trucks I believe. Match the torque converter to the trans, not sure what you can swap between your 66 trans and the other one if it is post 69.

 

the bigger spline means bigger torque converter, but does that necessarily mean bigger flywheel? If I change the flywheel, do I need to do anything else to make it all work?

 

The bigger spline does not mean a bigger torque converter, it also means that you don't need a bigger flywheel, the C4 has a small bell housing for a 157 tooth flexplate, and a big bell housing for a 164 tooth flexplate. You can use either a small or big on a 289-351W, a 351C requires use of the big bell housing and the 164 tooth flexplate. What matters is that you have to have the right flexplate for the right bell housing.
On the torque converter, one that's for a 164 tooth flexplate the converter will have a 11 1/2" bolt pattern, one that's for a 157 tooth flexplate will have a 10 1/5" bolt pattern.

 

Depending on what year C4 you have, there are 2 different spline
shafts. 24 and 26 spline. Check to see what you have, it will save you alot
of trouble.

 

Go to fordmuscle.com then to forums, then the C4 forum, you will find every thing you ever wanted to know about C4's in one spot

 

Kenneth you answered my question perfectly. Thanks everyone.