Hello all, I am thinking of buying some 302 heads for my 273 for a future build. Does anybody know some of the advantages of these heads over the stock 1967 273 heads. I know these heads allow for a modern intake manifold and no loss of compression do to the closed chambers. What about the valves? Are they bigger? Can I use my same rocker assemb. and push-rods? What about the holes for the air-pump that came on these models? Is it a big deal to have plugged? Thanks!