Found 8 1/4" Rear End

The 2.45 ratio used a different carrier to make up for the pinion head diameter. To swap in 3.55s you will need a carrier from a 2.76 or lower gear set. Any A, B, C, E, F, J, M, truck/van 8 1/4" with 2.76 or lower gears will get you the parts you need to swap 3.55s into your housing. The axle spline count changed in the mid to late 80s. Avoid the ones with the ABS sensor in the housing and you should come out OK. Or you could just get a new differential carrier. Mancini Racing, Dr. Diff, and Randy's Ring and Pinion are good sources for parts. Hope this helps.