Will a 318 from a 73 barracuda drop in a 71 Plymouth Scamp?

Thinking about throwing a running 318/904 combo out of an e-body into my a-body that came originally with a 318/904. Anyone know if the oil pan, headers, and such will "just drop in"? I'm assuming I'll have to run exhaust either way so no biggie there. I really just want something to take my roller from having to push it around to drive it around when I need to move it while I restore it. I'm assuming the 904 shouldn't be a problem unless maybe there were different splines on the output shaft.