I'm building a 351 cleveland for a 1973 mustang and would like to run a 4-speed top loader but the ones on ebay right now say they are for 65 mustangs or 68 mustangs with 289s or 390s. Is there a difference in the transmission from year to year or can a top loader for a 65 mustang work with a cleveland in a 73?

 

There are a few different ones...

http://www.davidkeetoploaders.com/idchart1.htm

 

289/302/351 4-speeds were basically the same, but the 390 was NOT the same, it has a shorter input shaft. The 65 - 73 smallblock 4-speeds were physically interchangeable.

 

This may be more info than you want, but here goes.

There are some variables in gear ratio, input spline size, output spline side, and bellhousings. I cannot recall all the details, but you need to at least watch for those things.

The gear ratio is either a wide or closed gear ratio. Both units have a 1:1 4th gear, but the wide gear ratio has a bigger jump between gears that the closed gear ratio trannys. Wide ratios were used more for street cars with small blocks that did not have a bunch of lowend torque, thus they needed a lower 1st gear. Closed gear ratios were used more in big block and drag racing packages.

I can tell you from experience that the large spline small diameter input shaft that came in most small block engine packages is pretty weak. I shattered a brand new one in two with my 383. For that reason, many guys will upgrade the input shaft to a tremec style with a custom made input shaft or go to a big block input shaft with a custom made clutch fork. Either way, it is a one off deal and requires a non-stock clutch.

The stock output shaft on the small block package is also susceptible to twisting and breaking. I snapped on of those in my car as well within 1000 miles. That can be upgraded to the larger 31 spline with just a change of the yoke and the larger u-joint.
http://www.5speeds.com/toploader.html
http://en.wikipedia.org/wiki/Ford_To...r_transmission

 

Doing what? The 25-spline had a pretty thin output shaft, but the 28 spline holds up pretty well, it was used in the BOSS 302 and BOSS 351.

 

Lol, Urban makes like his car/motor isn't anything special

 

I was driving down the highway when the output shaft broke . Glad I had a drive shaft loop. I broke the input shaft shifting into 4th gear on the drag strip. My point is if you are playing with stock torque the parts are ok, but if you stroke a 351, you will start breaking those parts.