[Sonic Blue 85]

The 650 is not too small. It will not hurt power with the NO2 or the supercharger. Which Edlebrock carb do you have? They have sold both copies of Cater and Quadajet carbs. The carter design is not a bad design but fewer people understand how to tune it, than Holley carbs. The The most common and easiest power adder for a carb set up is NO2, but you can install a centrifical supercharger. Vortec, Paxton and Pro Charger all have kits for a carb set up. It is also possible to install a turbo on a carb set up. You could also build a stroker like previously suggested, but it will use more fuel when cruzing than a smaller engine with a power adder. The power adders can be harder on engine parts. How fast are you wanting to go? It is very possible to go 12s with a mild cam, desent heads and intake, no power adder and a 306. It just depends on your preferrences and what you want to do.