[Walt Fricke]

1) Do a leak down to see where that 10 PSI went on #1-5. If you can't purchase (under $100)a leak down gauge, figure out how to connect an air compressor hose to your spark plug hole to get a decent seal, and just blow 100 psi or so air in at TDC firing. Listen to the intake, exhaust, and the inside of the engine via the breather. You can tell where the air is leaking out that way - intake valve? exhaust? Or past the rings into the case - there is always some leakage there. If your leakdowns are good, you might want to reconsider the top end tear down - unless boosting the CR is something you are going to do anyway. My compression testing protocol is bad - I forget if I did it hot or cold, and often forget to prop the throttle butterfly open.

2)Machine rocker and cam? What do you mean? Are you asking if the cam you have will work with your new aftermarket pistons, I'd ask the manufacturer if an E cam will work. Otherwise it is up to you to do the testing to see that you have adequate valve clearance, and if not, to machine the pockets to get it - giving up some CR in the process.

But if you specify the piston maker, maybe someone here knows the answer.