318 alminum intake?

The most inexpensive and arguably the best is the Edelbrock Performer. Other notables would be an early Edelbrock and the Weiand Action Plus.

The Performer and the Weiand are set up for spreadbore carbs while the earlier Edelbrock’(s) have a square bore carb set up.

I ran the Edelbrock LD4B. I tested the 600 cfm Holley 4160 & the OE Carter 600 on top of the 318 and found them both to be equal in performance at this low level. The Edelbrock was cheaper to run. Use a thick carb base gasket to keep the carbs cool and prevent fuel percolating issues.

Info right on the first page.
(rumblefish's Duster project)