I have a set of cb350 twin pistons (64 mm) and I'm looking for some information on compression ratio and mods needed to get them to work in a cb750. The pistons are marked AP. The valve pockets are pretty substantial, and so is the dome. I recall hearing that the CR would be around 12.5 to 1 with a K head. If I could drop this closer to 11 and run a long duration cam, I think I could manage running pump gas. I'm not sure what, if any mods are needed to run these with a big cam.
Any info is much appreciated. I'm digging through my parts stash to put together some sort of big bore kit. I'm just looking for more torque for touring and some extra fun.
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