Just remember, the magnum and LA use very different heads, and intake manifolds do not interchange. There are 4 barrel intakes for magnum heads, but your average Edelbrock or Holley SB Chrysler intake is designed for LA heads. Also, Magnums use roller cams with 1.6 rockers, while LA's are generally hydraulic flat tappet with 1.5 rockers. And LA's use rocker shafts, while magnums use individual bolts.

Just some things to keep in mind before you buy parts thinking a 318 is a 318 is a 318. There have been 3 major variations of this engine.