Well if your going to do head work it would be crazy not to take advantage of your new free breathing heads with a more aggressive cam. As for heads, the best heads on the market for LT1's is AFR but they are pricey as hell and then there is Lloyd Elliot's which makes some serious power with his port packages combined with larger valves and better head components
http://www.eportworks.com/ . Honestly though, a basic LT1 head porting job (gasket match intake port with a matched intake manifold, polished exhaust Â*port) with some higher lift springs with some 1.5 or 1.6 roller rockers. Will make some very impressive numbers for a fraction of the price and when matched to a cam like either a comp cam 305 or even a LT4 hotcam. Will make some serious power. Thats what I would do if I was in your position.