I'm building a big block ford 572, 4.5 stroke, 4.5 bore, 6.8 rod in a 10.30 deck block. Not running yet but I know alot of other ford guys running the same combo and making alot of power without any problems turning higher rpm also. Several are also running the 4.5 stroke with less bore having great results. One guy dyno'd his 557, 4.5 stroke, 4.44 bore, 6.8 rod and made over 850hp at the flywheel using unported Trick Flow heads and a single carb. I know its a ford instead of a chevy but should give you an idea. Either way I would use a custom cam from a reputable cam company, not that much more expensive and you know there's no guesswork. Chris