Interchangability

I was mainly curious at to what interchanged, I'm hoping the 318 in the Dart isn't cracked as it ran like a top. I need the 727 for my 65 pickup, the 8.75 is a money piece or I could save it for the day the car has a 440. 8) Overall the Aspen is in good shape body wise it is spitfire orange, but it has some serious rust and cracking issues in the front suspension. -BD