Yeah, I haven't yet gone the way of doing a leakdown test. I was thinking about actually blowing some compressed air into the cylinders one by one. Sort of a poor man's leak down test. If I can hear where the air is flowing, I might have a better idea what the problem is.

The rebuild di include machine work. I had the block hot tanked and inspected. It was not magnafluxed, but the machinist mic'd the cylinders up to make sure it didn't need to be bored. The engine had only 109,000 miles on it, and he said the lower end looked good. It had spun a bearing and consequently wore out the bearing mating surface on that connecting rod. I wound up getting a reground crank and a replacement connecting rod.

Had a professional valve job done shortly before spinning the bearing. My feeling is that the oil problem was pre-existing, but since I rebuilt the engine, it actually seems quite a bit worse.

I'm puzzled, though, because clearly the crankcase is getting pressurized--it shoots smoke out of the fresh air breather even at idle! But the cylinders are holding 125 psi, which isn't terrible, and the rings aren't done seating yet.

Its been too cold here in VT to do much on it, but I've got to get this truck going. I've been driving my in-laws car for 4 months now!