[COUGRRRMAN]

Anybody know the difference between a 351w front differential u-joint yoke and a big block heavy duty yoke? are they interchangeable? Is the u-joint the only thing to change if I change yokes for more durability?

 

[COUGRRRMAN]

SOMEBODY MUST KNOW

I know someone has experience in this area

 

[Cougrrcj]

Generally, small blocks had the smaller u-joint size while big blocks had the bigger size. Things get more confusing with 351C-4Vs. Automatics had small joints and 4-speeds had the big u-joints. You can get a hybrid u-joint or you can make your own hybrid by just swap caps on the opposite ends.

Then there are the differing length yokes. Some car lines had short yokes and some used longer ones. Econolines have long yokes. I know that for a fact since I swapped a 72 Cougar 9" rear end into my 74 Camaro. Overall width was very close and the spring width is within 1/2 inch. I used a longer Econoline yoke and then I didn't even have to touch my driveshaft length!

 

[modifiedmark]

Yeah I didnt, want to really touch this one as I never have figured it out for sure. It seems to me there were 2 general sizes on the joints. One had 1 1/16" caps and the other had 1 1/8" . One was 3.5" wide? and another I dont remember. Then there was the one with both 1 1/16" and 1 1/8" caps.

I just take em out and measure any more and go to a real parts store and get what I need to fit. mm