Test test test

Earlie A said

See the drawing below. If the chamber is 4.180" wide and the bore is 4.080" wide, there is a 0.100" mismatch which is not good for flow. Is the best option to use a 4.180" gasket and use a 0.050" chamfer on the top of the bore? That's a pretty large chamfer. Your engine is a 4.030" bore with a 4.180" chamber, which would make for a larger mismatch.

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The chamber wall is, in reality much taller than your drawing...if you do it right (chamber shape from the seat to the deck) the bore intrusion is no big deal honestly and it does make more power than keeping it tight like say a 4.080 gasket bore. I don't do this as much now as I've learned how to make the same power while keeping the chamber tighter than I used to. But it works.