I just picked up my new 26 spline C4 last night for my 450 hp 393 stroker. I had it built to withtand 700 hp. My previous C4 was stock and also a 26 spline but finally blew after about 125 runs at the track on drag radials. This one is beefed up with needle bearings, etc. I had it built for $850 which is barely more than the TCI ones you can buy from Summitt that are rated for 450hp.
I had a few shafts that had 24 splines going into the transmission, and 26 for the torque converter. You may be able to pick up one at a local tranny shop, since I had two out of two transmissions I purchased for parts, I don't think they are too hard to come by.
On 2003-07-12 06:31, BillyHoe wrote:
I´m replacing my 1967 tranny, it´s a C4 24-splines,157t flexplate.
Is a rebuild C4 26-splines with 10.5 bolt pattern the right way to go???
I have a 500hp 357W in a 67-mustang.
Yes, the later, 26 spline C4 is the one to beef as it is markedly stronger than the earlier version. As noted, it does have an input shaft with 26 splines on the convertor end and 24 on the forward drum end. The later case will work with your earlier bell, flexplate and convertor. So, you can just get the tranny, or go ahead and get all new stuff.
In early mustangs I don't think it matters whether you use the larger 164tooth/11 1/2" flexplate and matching bell or the smaller one, as long as the whole setup matches.