help with 318 upgrade

Run a compression test on all cyls to make sure you are not wasting your time, otherwise the rest of your plan sounds pretty good, I don't think you will be unhappy with those upgrades.

When you do pull the heads off the 318 get the deck height of each cyl so you can calculate CR and tune the build a bit - don't be surprised if you find flat-top dished pistons in there as factory CR was in the 8.6:1 range - the closed chamber of the magnum heads will bump your CR up and help use all of a 600cfm carb

I'm sure others will have better advice for you