Calling all 318 guys....318 vs 5.2 magnum, info needed please

Thinking about buying a 5.2 magnum complete for cheap..or i have a friend who sells me a 1971 318 base with 30 over pistons...., i want to go with a 318 to replace the 340 that i never had , always played with 5.9s....but im sure than a roller cammed 5.2 carburated can kick *** for my 71 cuda ......5.9 needs a 700$ flywheel and a 5.2 is internaly balanced like a old 318.....whiplash cams sound incredible with the old 318s....im shooting for 300hp but the cheapest way possible to hook up with my 1971 a833 4 speed and 3.23 gears.... old 318 ? Seen a 1990 roller 318 for sale , 5.2 magnum ??? Or plain Jane 5.9 ???? Im going carburated and 4 speed..let me know please