u-joint size?

RedPonyGT said:

hey guys,
I have a 65 mustang I put a 351w in but the rear end is still the 7 and 1/4 inch. I did the T-5 swap with a new aluminum driveshaft but I need a u-joint to go from the standard 1310(i think) to the smaller rear end size(which i don't know what it is)
Any ideas besides a rear end swap?
thanks

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Hi! your curent rear end as a 1100 series or 1260 series u-joint, you need a conversion u-joint, if you need 1310 to 1260 conversion spicer 2140x should work for you. If you need 1310 to 1100 might be out of luck. You said good buy to that 302, you should let go that 7.25 rear end go before it goes on you.

1100 are 1.717" from inside clip to clip
1260 are 2.342" from inside clip to clip
1310 are 3.219 from cap to cap
1330 are 3.625 from cap to cap

He should upgrade the front suspension and brakes ASAP too, before he even runs it. Going fast is one thing, but if you can't control the car, it's really useless and dangerous.

One thing you can do to get you going at least is to take a micrometer, and mic the diameters of the caps you will need, and mic the span of what you need. Then go to a parts store and see if you can look in their u joint catalog and look through the section that has all the dimensions of the joints until you find the match. Autozone for one has the perfect u joint catalog for this.
I used to pull random driveshafts that were the right length out of wrecking yards, and then mic everything and find what u joints I need in that catalog using the measurements.



But I agree with them. It will be miserable to drive. I did the exact same thing. It wasn't long before I did a front suspension upgrade and a 8 inch swap because the little rear broke. The car was no fun, it couldn't stop or turn well at all. I had some very scary stops in that thing. Even if you have to take the poor mans way out like me, a Granada disc swap with all new factory style suspension parts and new springs, and an old 8 inch will do wonders for the driveability.