Edelbrock #7101 for conventional Gen I heads mounting a square-bore carburetor. The very same manifold can be had under Holley part #300-36 and Weiand 8016. Neither of those manifolds is being made any longer, but many times they come up on ebay or craigslist.
Edelbrock #7104 for conventional Gen I heads mounting a spread-bore carburetor such as a Rochester Quadrajet.
Edelbrock #7116 for Vortec heads mounting a square-bore carburetor. Counsel with head supplier, find out whether the heads take a Vortec intake or a conventional intake.
Concerning headers, you want a quality set of long-tube headers. Not shortys. Look for 1 5/8" primary tube size and a 3/8" thick flange. Thinner flanges will curl up from the heat and spit the gasket out. It's up to you whether you want them painted or coated with Jet-Hot or some other protective coating.
.