Heads issue

I would have the heads flow tested first. By a guy who isnt looking for anything other than a number. Ported and polished may mean trashed and you dont realize it. It's much easier to start with virgin and do it right, then start with ported and try to make it better. Second, if you have domes on those pistons that project more than .020", you will have issues unless you are careful with the head choise. The "340" Edelbrock RPMS have an extra .060" milled from the chamber area making them full open chambers. No the best for power, but good to lose some static compression. You can run a static of over 10.8:1 with a good engine plan. You cannot when you are "making it work" so to speak. Cometic makes thicker gaskets too, which can lower the ratio...However, they MUST have a very smooth surface (not just flat, smooth) on both heads and block to seal properly. A fully ported set of irons will (realisitcally IMO) flow slightly more than a set of stock or "cleaned up (read as Stage 1)" Edelbrocks. A set of ported Edelbrocks will leave hogged out factory castings in the dust. I always want to know where I'm starting from, so I'd have a head flow tested first. Then go from there.