Im rebuilding a 70 firebird. It has a stock 2.73 8.2 10bolt rear end...granny gears im gonna switch them to a 3.73 with a posi and thats gonna be linked up to a tremec 5pd.. i want to know if i can put a 8.5 in the 10 bolt rear end im buying a new 3rd member..will it fit?? help??