i had an 89 firebird,2.8 auto, i replaced with a 350 carbed with a turbo350 auto....should i use a v8 700r4 tranny crossmember or the 6 cylinder one that is spaced up with bushings....the v8 one is giving slight vibration problems...im thinking its the pinion angle but the v6 one seemed too high to the floor boards...help me please!!!