For stuffing 295/50/15 in my 73 challenger, I found a 66 Satellite rear housing and axles. Pressed on new taper wheel bearings,my original chunk with a new sure grip unit, friction modifier,Dr. Diff 1" relocation brackets, and u joints in pefect shape.At 25 to 30 mph, get a modeate vibration felt mostly in the steering wheel, center console also vibrates.Anyone else experience this?

rule of thumb, vibrations in st wheel point to front end issues but in your case no ch to front only what you stated on the rear axle swap right? Might check the driveshaft angles & assuming plenty of front yoke engagement in the trans not borderline not enough as there'd b virtually no significant front/rear length ch w what you did.

make sure U bolts are torqued (and retorqued after about 20 miles) also, what is your pinion angle in relation to the spring perches?

If you haven't already done so, move the spring eye to the upper hole in the front hanger or install a 3 degree angled wedge to pivot the pinion upward. This will compensate for the different pinion-to-perch angle of the B-body housing.

Thanks Cass. I forgot to mention,I have one inch lowering blocks in now but Im too low and there coming out this weekend. i am in the top hanger hole now. Should I try a stock type mounting or try add a ,say 2* shim?

I would get rid of the lowering blocks and run the spring in the front hanger's upper mounting hole.

Just as everyone said.. must be drive shaft angle...does the driveshaft seem to have an extreme angle?

Will get an accurate check Saturday and test from there...thanks!

It was a bad angle. I nosed it up with a 4* shim, vibes gone. Thanks for your help guys!