318 heads

Use what ever head you have. If I had to choose from the verity of 318 heads ready to run on a table, it would be 302’s. Use a piston that can get you some good quench. That might be a problem with the various cc amount of the 318 heads. Generally there all a closed chamber.

The stock cam is good for mileage. If your going to move away from a stock cam, you could look into the aftermarket since they actually have cams under that listing, “Mileage Cams.”

There was a thread over on MoPars a good while back where a guy went down this path. He used a high compression 318 and really tweaked the crap out of to the tune of (IIRC) 32pmg’s. *I Think* an overdrive was used.