need 8 1/4 advice

DirtySwiffer said
i think your right, i just searched a ring and pinion set with 3.90 gears and can get that for 200ish with install kit. just need to get in the cover and confirm that i have 2.7 and higher carrier. if it turns out that i have a suregrip carrier, can the springs be adjusted? the evidence marks on the road dont appear to be 'suregrip'. with your gear change, how was it mechanical wise? i dont know any of the tolerances inside the rearend housing.

I had a friend who does heavy equipment transmission and axle repair set mine up so I don't have any 1st hand experience inside the 8.25. I would pay a guy like that to set up the rear. Takes a bit of knowledge and the right tools and shouldn't cost too much in labor. If you are getting one wheel burn outs then most likely you have a one legger diff. My only experience with a bad "posi" type rear (chevy speak) was the car would rev but not much happened in the way of wheel spin. It was just slipping so bad inside the diff no power was getting to the axles. I don't think you can adjust the springs inside one by shimming but I could just as well be wrong.

8.75 and 8.25 share the same 3" axle tube diameter so the shock plates and u bolts interchange. The 8.75 in A body form is SBP where as the 8.25 is BBP. They both will physically bolt into the stock rear suspension but due to differing pinion lengths will require drive shaft shortening or lengthening depending on which direction your going.

Most definitely replace the pinion bearing. The kit you showed does not include one.