Just bought a '71 RR that was set up as a race car early in its life. Car has no rust except the bottom inside lip of the trunk lid. The problem I have is the car has a narrowed dana under it with 31-14 X 15 racing slicks. No leaf springs, has coilover shocks. Can the existing axle tubes be extended approx. 4 " per side and new axles installed or do I need to have the tubes removed completely and new ones welded in. I think it has a spool in it so that would have to be changed also. As a last resort I was thinking about just finding a used 8 3/8 and installing leaf springs. Going to be running a 440 with about 400 hp .