One thing you might want to do is check out your timing. With 62 heads and the factory intake, your timing might be badly retarded to prevent detonation. Either have the distributor re-curved to match the set-up and the fuel (talk to Banshee about this - he's got a good place to send distributors) or run some octane boost or racing fuel so you can run full advance.
I once had to limp my 11:1 455 home on 91 octane pump gas. In order to keep from pinging, I had to retard the timing - a lot. (And mess with the mixture.) The car could not get out of it's own way, no matter how I tried. After filling up on a mixture of 91 and 101 octane fuel, I could feel the car still running like s*** as I left the filling station. Within about a block, I could literally feel the car surge as the fuel made it from the tank to the carbs and started to get dumped into the engine. Within a block I had to pull over and advance the timing up to 12* because the oil and water temps were in the red.
