Craig,
On the crankcase pressure, check the breather to be sure the reed valve is assembled properly and is seating against the ported plate. Be sure the valve lash is set properly, .008 for intake, .018 on exhaust. I wouldn't think valve sticking would be the culprit on a newly-rebuilt engine.
I've never been a fan of boring a 3.375 bore out to 3.5 inch diameter - that's a lot of cylinder wall material being removed with a resultant loss of strength and integrity of the bore. Heat will cause the thinner walls to distort more easily, especially in that area of the bore adjacent to the exhaust valve. Blowby will be noticeable in this area after a few hours of running. I hope this is not the case with your engine. Might be a good idea to run it for another 5 hours then remove the head again to inspect the bore.
Don't mean to be a profit of doom and gloom; some guys get away with this...others don't. Seems to depend on how concentric the bore is with the casting.
On the crankcase pressure, check the breather to be sure the reed valve is assembled properly and is seating against the ported plate. Be sure the valve lash is set properly, .008 for intake, .018 on exhaust. I wouldn't think valve sticking would be the culprit on a newly-rebuilt engine.
I've never been a fan of boring a 3.375 bore out to 3.5 inch diameter - that's a lot of cylinder wall material being removed with a resultant loss of strength and integrity of the bore. Heat will cause the thinner walls to distort more easily, especially in that area of the bore adjacent to the exhaust valve. Blowby will be noticeable in this area after a few hours of running. I hope this is not the case with your engine. Might be a good idea to run it for another 5 hours then remove the head again to inspect the bore.
Don't mean to be a profit of doom and gloom; some guys get away with this...others don't. Seems to depend on how concentric the bore is with the casting.