I have a 1969 Nova. I have a 350SB and a TH350 with 3.08 posi in the rear. I don't seem to have any launch power. I have been told to switch to a 700R4 because of its first gear ratio as well as highway ability. My question is; will this be a difficult conversion, other than shortening my driveline and moving cross member any other obstacles to look for?