27warlock,
You can certainly change heads, although I wouldn't recommend the Edelbrock's. Dart Pro One's and Brodix -3 heads all work well.
Another idea, you can install the 500 HP EFI camshaft, change exhaust to CMI, and put our 500 HP EFI kit on and can back it down and make enough power for 80+ all day long. You'll have a 500 HP, capability of 700+hp. If you want the heads too, then you can add some more ponies, but the problem is that it needs new computer programming, as the VE of the engine is changed when the heads are changed. This is not the biggest deal, but needs to be addressed.
The 496 system should be available in March, the final calibration (ECU) is in the works. We've just been so busy, we have not had time to finish all the castings, instructions, etc. but have been back on it lately.
Thanks,
Dustin