I need a 8 3/4 out of a b body . please help !!!

If the slicks are running the leaf springs why don't you either use some 3/4 offset shackles or just do a 3" leaf spring relocation kit... Would be faster and cheaper. Unless you don't think your 8.25 wil hold up to the motor.
I have a 3" kit here at the house but the car is done I don t want to add any heat to the car..........