finally it looks like V-8 time

Go with the 302 heads or better yet a set of Magnum heads. I think the Magnum heads have to be redrilled to use LA intakes though. Still super head design. The EFI engines greatest parts are the heads transmission and rear gearing. Thats was get the real fuel milage. Stick with the carb. Mopars biggest weakness is the electrical system. Don't add more problem to it.

The 999 is a updated 904. You can buy a weighted flexplate for the 360. You are better off with the 318 over the 360.

Get a 5 speed and cut up the floor to fit. It will be soooo worth it.