Mismatched Cam and Heads?

That cam is fairly large. The .509 is a race cam in most small blocks with stock stroke, and is not used by guys that really know what they are doing. I would replace it with something smaller by about 10° less at .050. The heads are fine, they will work very well on a 360 in stock form. But, make sure you replace the springs with thte ones the camshaft manufacturer recommends. The Edelbrock ones are not very strong, certainly not enough for most modern grinds.