Engine Swap Question

I recently put a 1974 318 motor in my 64 Barracuda. It fit, but just barely. Unfortunately, the engine has a severe vibration/balance issue that we have to solve. Since the motor we rebuilt had some internal issues I may want to put in a different short block, and still use the aftermarket parts we put in, such as cam, 4 bbl, roller lifters, etc. My question is: What years of motors will bolt up to my 1974 A904 trans, still fit in the tight quarters of my A body, and allow us to use our parts? Can I run the newer fuel injected motors on a 4 bbl carb? Any suggestions? Thanks A-Body-ers for all of your great advice!