front end swap?

[ffbrass]

Ive done a search and talked to a few guys who have done the newer cross member swap and Im confused. Ive been told that a cross member all the way up to an 87'will pretty much bolt right in. But Ive read on here or classis chevy board that around 80' the crossmember changes to metric (or somthing, what does that mean? Ive got a 64' with no motor or tranny....so Im thinking if I can find a 70's or 80's 2wd for like $500 that is complete I could get the front end and a motor to build all in one to make life easier. Also arent vans on a truck chassis cause if I could find a van I could probly get a gas tank too.

Any help appreciated....