Not a A-body but a couple of questions about a 318.

I've done a few 318's and my advice is do not use the 302 heads just use what is on there now. To expensive for what you get in return. Almost nothing. Do a cam with the Edelbrock intake. I suggest the Edel. AVS version. Doing all 3 at once yields the best results in what you will feel. Also do not be afraid to go to a 2-1/2 exhaust.

A better head upgrade is ether a set of ready to bolt on 360 heads or Edelbrck heads.