I have a '49 chevy truck with a 75 nova subframe, sb350/th350 combo with a gm 10 bolt rear end. I want to go with an overdrive trans like a th700-r4. My questions are, besides moving the trans mount back, what other modifications will be required? Are they the same length or will I have to shorten the drive shaft? Will the shift linkage match up? Any other considerations?