beefing up my 318???

I'd have to say, the a general question with general information is going to get you a general answer. So here we go and here I try.

Purchase a used;

Edelbrock Performer or older LD4B

A 600 cfm carb, Holley or Carter/Edelbrock, your choice. Use with a open air cleaner/element.

Headers help though not a "Needed" item. NEW dual exhaust should be done @ 2-1/4 inch pipe. MIN.! Use with a "H" pipe or "X" pipe to connect both sides. Mufflers are your choice.

Purchase these new.

Add a MSD or equal like ignition. Use a MP viscous fan. Both of those should be purchased new.