Budget Build 5.9 for a 71 Scamp

The 2000 model year still has the LA mount locations, so that should be no problem.
Do you have the flex plate that was originally on the rear of the crankshaft? It will have the correct 5.9 Magnum balance weight. Depending the transmission you go with, you may be able to use the flex plate by slotting one of the mounting holes for the converter or transfer the weight to the converter.