Need some advice here on this unique question that I can't seem to find when I search Chevelles.com.

Well, I just bought a Moser 12-bolt for a 69 Chevelle with 3.42 gears. When they asked me what yoke type i wanted, I told them to put a stock yoke on, which was the 1310 yoke. When I got it home and installed the rear end, I was putting the driveshaft back on when I notices that the driveshaft U-joint is bigger. It turns out the U-Joint is for a 1350 yoke. I really kicked myself for ordering a smaller yoke.

Anyway, I wanted to know what is your suggestion on fixing this setup. Do I just purchase a new U-joint conversion, that goes from 1310 to 1350, or do I make it right and purchase a new 1350 yoke? My car has a 383 with about 450 hp and a TH350.

The question is if I wanted to replace the 1310 yoke with a new 1350 yoke, can I just take the new 1310 yoke out and put the new 1350 yoke on this brand new rearend without compromising the crush sleeve or bearings? I have not even put rearend oil into it yet or driven it. It's still brand new. $$ isn't the issue, I want to do it right.

Or can I just leave the 1310 yoke on a 450 hp car? Thanks for your help.

Well if $$ is not an issue......buy the correct yoke but your 383 aint gonna break that ujoint anyways. You could leave it as is. I had a 600hp 400sb that never broke the stock joints, I doubt you will.

To change the yoke remove the original yoke, clean the splines on the pinion shaft, smear some RTV sealant into the splines of the new yoke and put it on the shaft, put some red Lock Tight on the threads and torque the nut to 150 foot pounds. This should take care of it. If you want to be sure that you didn't change the preload setting you can remove the differential and measure the preload before you remove the original yoke and check it again after installing the new yoke. You could even use a new crush spacer and start all over again and do it right. I'll warn you that it takes about 300 foot pounds of torque to crush a new spacer, so you will need some good tools to do it.

Anyway, I wanted to know what is your suggestion on fixing this setup. Do I just purchase a new U-joint conversion, that goes from 1310 to 1350, or do I make it right and purchase a new 1350 yoke? My car has a 383 with about 450 hp and a TH350.
That's what I'd do...buy a quality 1310/1350 u-joint for the rear. IMO, at that power level, you'll be fine.

Thanks all for the advice.

you might want to give moser a call, if you go changing things and theirs a problem, they may not warrent it-the conversion u joint may not be a bad 1st option, till you know the rear is ok