Ops, what about that old Turbo 350? Now lets be real. In this case I would also take out your old tired Turbo 350. Drain all the fluid and put it in a baggie under your bed. Retire it for the Turbo 400. It is the tranny of choice. Came under all Firebirds and Trans Ams with big motors and will fit under you car like it was made to be there, because it is.
