aluminum heads

"stephen was a race car driver, he drove so god damned fast He never did win no checkered flags but he never did come in last.
stephen was a race car driver, he'd say "El solo number one" With a bocephus sticker on his 360, he'd light 'em up just for fun"

PRIMUS.

Since budget is your concern, and you are working with a stock shortblock (with cam added), I would agree with Rumblefish - rework your existing heads. Milling can gain you a half point of compression or so, and a home porting job only costs your time and effort. It will be worth the effort.