closed chamber vs open chamber

Easier to offset grind the crank and bring the pistons out of the deck. you also get more cubes. so you increase the CR formula with more stroke. But no matter what you choose its $$$$. If it was me I would add boost. or NOS.

Cut the head and you have to cut the intake and it will never fit another set of heads. and don't forget push rod length for rocker geometry.

The cheapest and easiest would be get some pistons. or get heads.