I have a 68 coupe with an I6 200. I am building a 302 for it and I want to swap out the 7.25" rear end for an 8" that came from another 68 Mustang. The motor is still several months out, but can I swap the rear end and still use the same driveline? Do I need to swap yokes or anything else or is it just a matter of swapping out the rear ends?
Thanks!
Gordon

 

Auto or manual?

If you keep the I6 driveshaft you will have to get the rear u-joint modified to a 1310 u-joint. It had that done, but it cost me $100+ and then I only used it for like 2 months. I now have a V8 driveshaft because I swapped to a T5 and will be swapping in a 302.

 

BA,
It is a C4 automatic. I want to drive it while I am building the 302, but I want to put the rear end and the 5 lug front end in now. What is the 1310 u-joint and what needs to be modified to use it?
Gordon

 

If you find a V8 driveshaft with the C4 yoke you could just use that. 1310 is the size u-joint that fits with the 8" rear end. The I6 has a really small one, something like 1210.


On my I6 driveshaft they cut off the old yoke and welded on a new one that held a 1310 u-joint. (see attached pic in my post above)

I am using the driveshaft in the pic attached to this post right now with a T5 yoke. It is a V8 driveshaft.

 

was the new yoke off an old driveshaft? Did you have it balanced after you had the new yoke welded on?

 

This is getting all confused. You won't need to change the yoke if you are runnning the same trans. The rear U joint is the issue and it may work. I have done the swap you are talking about and reused the same drive shaft. The best thing is to measure the yokes on the rear ends that you have now and see if they are the same. You will need the distance across and the size of the cap.

 

The u-joint is not the same and will not work. If they were indeed the same I could have used my I6 driveshaft and not had it worked on.

 

I went to a driveshaft shop here locally and they welded on a brand new yoke. They also checked to make sure it was balanced.

 

you can also look for a conversion u joint. if you can find one it'll let you mate the smaller I6 driveshaft to the larger 8" yoke. most auto parts can get one - you just need to know what the two sizes of u joints you need are.

 

I swapped a 5 lug rear into a 66 with and I6 and had to change nothing. It is worth measuring before you start just so you know.