I have a 385 SB with a built 700r4 and a GV unit, it sits on an aftermarket creossmember. I just had to massage the tunnel a lil bit. One thing no one has mentioned is the condition of the body mouns, it can and will affect the fit. I still havent driven my car still waiting on the wheels. I installed the swith on the hole where the stock radio was, fits very nicely their.