Does a CV20 crankshaft fit a CH20? Looking to get a PTO output shaft on a Walker-spec Kohler as they drive from a stub shaft on the flywheel side only. Thanks?

I have a stock horizontal engine, running it fairly hard, but not extreme. Budget engine, was stripped, cleaned, honed and back together with the old rings. Not burning any oil and compression is balanced at 110 PSI. I am pretty sure it has the smaller heads, but would have thought compression would have been higher with the smaller chambers and metal gaskets.  I removed all the factory venting, baffle, plugged holes and vented out the governor hole with a hose barb. It puked a lot of oil, so I put the baffle plate back in and started venting from the stock location. However, it's still losing a LOT of oil. It is even losing oil through the vent on the fuel pump (planning to feed from intake side). I've read that if my rings are going, that can increase crankcase pressure, but the motor is really snappy and not burning any oil, is this much loss normal? I run the correct oil level and it will get down to the add line after a couple races. I am going to need a pretty good size puke can....also where should my oil pressure be roughly? Thanks you.

I have a relatively fresh block with stock rods and pistons. The heads are from a 14/16 hp and have the smaller chambers, thin gaskets, valves freshly lapped, lash set at 3 thou. Compression is balanced both sides at about 110 psi, just quickly bench tested with starter and a bit of lube on cyl walls. I am wondering what a safe amount would be to shave the heads to get a little more compression, pump gas, and I would like to retain the existing pushrods/etc. I know this is a deep subject, but I was hoping there is a safe amount to go with that is a standard of some kind.

Regarding compression in general, what would be a good target to shoot for? I am running and ARC flywheel, cam retarded one tooth, everything else is stock other than shimmed valve springs.

I've got an oil cooler setup from a 38ci Vanny and am wondering if it is worthwhile running on a stock 35ci motor? I'm guessing that it could be a potential weak point for the short time the motor runs...

Looking to clean up my cylinder bores. Wondering what is available by way of oversize pistons? I see parts tree has +020's - would that be the only size that's available?

Also, what is the recommended 'race prep' cylinder bore to piston diameter clearance?

Finally, your preferred break-in procedure?

Thanks

New to the board, and relatively new to racing. I am going to join my son racing next season. I am building a Supermodifed powered by the above noted motor.

I'm wondering if someone can direct me to an existing thread regarding build tips for this engine.

In my class, there are no internal mods allowed. Must use stock components meant for this engine only. Exhaust and intake are open. As are ignition and flywheel (I do have a ARC flywheel on the shelf already).

I have built a few engines over the years, but never a small engine specifically meant for racing so I should be able to do some learning along the way.

Thanks for your help.