I recently rebuilt a 305 for my '81 K5 and am already wishing I had put spent the extra money on a good 4 bolt 350 when I had started but I can't go back now. So, its a mostly stock (edelbrock intake, headers, smog stuff removed) 305 off an '84 truck. I would guess these would have about 8.5:1 compression. I am already seeking more power and know that more compression is a good way to get more power. It has the stock dished pistons (yes, I know I should have replaced those too!!! I just didn't have the cash and the cylinders/pistons were to spec so I just had them honed) Well, I don't want to rip out the entire engine again so I need something that I can bolt on with the engine in place. I was thinking maybe an Xtreme energy cam. Also, my friend suggested today that you can get your heads angle milled. He says they mill lots on the exhaust side and hardly any on the intake side so your ports still line up fairly well (may need to double gasket the intake). I was just wonderin if this would be worth it or if I should just look for some smaller CC heads? What kinda of vehicle should I look for some 64cc heads on. Remember I need the small valves because its a 305.