blowby concern
#1
#2
A combination of a cylinder at or near BDC with in intake valve open could cause that, becuase the cylinder does not seal perfectly, especially when cold. I hooked up the CCV gauge setup i made for Ernest eugene today, and at idle with a cold engine i had 5.5" h2o at idle, and with it warm it was near ambient, at 3.5" of h2o. I do not think you have a problem. Start the engine, get it warm, and remove the oil fill cap. You should have a steady stream of oil mist, not a puffing oil mist which means cylinder combustion pressure is leaking past the rings every time it fires.
#3