Useing just near-normal numbers, your compression will go up about 1 point on a (3.5 stroke to 3.85). With something like 62 cc chambers and deck clearance close enough to keep quench, you're looking at 11.5:1. You'll have to run a big duration cam or buy dished pistons. Something like a 22cc dish will be required to get down close to 9.5:1.
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