put the gauge on the dipstick, and it was showing a slight bit of pressure at idle and slightly above, 1500 rpm or so.

closed off the two breathers as best i could, (milk bottle tops and duct tape, high tech engine analysis equipment ), and drove it around. it was slightly pressurized the whole time. about .5 psi. it didn't vary much at all that i could see. probably didn't have it above 2500 rpm, but drove around for a few minutes, and didn't notice any change.

i would expect that the pressure would increase... i'm not sure exactly how well i had the breathers sealed off, but they were pretty close to sealed.

but with no place for that pressure to go, except back into the cylinders, and a slight bit out the not-totally-sealed breathers, it seems that it should increase.

unless it's being sucked in at the manifold?