You may be better off having a new drive shaft made to the proper length, rather than trying to adapt either shaft that you have. That way the yokes and u-joints can be matched to the trans and rearend you are running. It will also be properly balanced. Driveshafts usually aren't very expensive, the average here is about $100. Try asking local racers where they get their shafts from to find a good driveshaft shop.
