Unless you're a glutton for punishment, sell your 8.75 and move on to a stronger rearend that will actually take some abuse. If you make decent power and the car isn't a featherweight, you will fill the bottom of the housing w/ teeth.

You CAN build a Dana for your car from a truck housing for a LOT less than what a new rear costs if you're willing to put forth the effort.

You will not go slower due to the weight of a Dana...that's been proven over and over, yet people refuse to accept it. runaway

A 9" IS A BETTER OPTION, but do the math on it and see what you're willing to spend. You have to realize a good 9" won't use any factory parts other than maybe the rear housing (not the center section). That rear housing also needs a backbrace.

CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax