KL80C3 said: To change pistons requires machine work, boring an honing
Milling the heads also requires machine work...
The only machine work needed to swap pistons is pressing the pins out and back in. Honing would be optional, depending on how the cylinder walls look. The only reason you would need to bore the block would be if you went with an oversized piston, or the cylinder walls were severely worn...in which case raising the CR would be counterproductive.
Not sure simple gasket change would change the CR by .5, unless the original gaskets were really thick. By milling the heads, and using a
quality, thinner gasket, you might get a .5 increase....depends a lot on how much is cut off the heads. You can only go so far before you have issues with the intake sealing properly, as Darryl mentions. The more the heads are cut, the farther away the intake ports are(wider) across the intake. This requires a thicker intake gasket, and milling of the bottom of the intake at the front and rear, where the end seal is. Get into angle milling, and you've opened a whole new can-o-werms.
Personally, I'd go with a piston swap....you can get a set of pistons that are designed to work with the chambers and valve sizes of the new heads, without all of the machine work involved in cutting the heads/intake. But that's just me.
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