I don't have the tools for checking the bore size but the block and head were resurfaced last time the head was pulled. An out-of-round cylinder wall would definitely cause problems but I would expect it to be blowing smoke at high loads due to poor ring seal and it doesn't do that.

The valve stem seals were replaced 10,000 miles ago. I am replacing my OEM valve springs with supertech dual springs and retainers, so I'll check to make sure they are all seated correctly. If those were bad, I would assume steady smoke under vacuum but the smoke is intermittent and only happens on throttle blips.

You should do your own block. As long as you can get the proper tools and a Helms manual, it is easy enough that you shouldn't have to pay someone to do it. As long as you are using OEM parts, sizing bearings is simple. The main cap bores are stamped on the underside of the block, the crank main and rod journal sizes are on the crank itself, and the rod big end bore is stamped on the side of the rod. With those numbers, you can use the tables in the Helms to determine what color bearing you need.

I believe that the problem didn't exist in the block because the wet test didn't change. Either the headgasket was failing or a valve isn't seating correctly. I'll see when my parts come in Wednesday and I put it all back together.