I have a column shift 3 speed that has been cobbled up with a floor shifter and want to put in a floor shift 4 speed.My question is; what will I need to change over other than the gear box and floor pan?? I have a 61 chevy 1/2 ton with a 235 6 cyl and the donor is a 62 gmc 3/4 with a 305 v6