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Discussion Starter · #1 ·
I have a used, but fresh bored ESR motor, originally a 330PV motor.
Cylinder and piston is now a 76.5 bore, 76mm +4 crank, which equals 349.812 CC displacement.

I have the pump gas and race gas heads, and they are oringed, so I cannot adjust squish there.

It currently has a .230" spacer plate on it.

Question, my current squish is as follows.
Race Head = .03"/.762mm
Pump Head = .04"/1.016mm

Compression on the Race Head was 220.

I have not ran it like this yet, as I'm concerned squish is too tight.

Thinking about putting my .250" spacer plate on it and then trying squish measurement again.

Any idea or recommendations on squish, or if I should leave it alone, if not, what is the best method to raise it a bit?

Maybe a thicker base gasket versus the .250 spacer?
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