[quote]The car does belch a little smoke on warm startups. We can drive it somewhere. Sit maybe an hour or 2 and it will puff out a decent cloud of blue on restart. Then nothing. In my gut it tells me its a valve guide issue.

The above statement is a pretty strong indicator. As an Old German physicist that i work for used to say. "DO NOT allow yourself to start chasing ghosts" gather your data and analyze it.

IMO, the above pretty much identifies the issue. My guess is one of the 3.
1.I strongly suspect you have either excessive guide clearance/ bad seals.
2. Possible intake leak.
Pulling the intake will likely confirm the backsides of the intake valves are coated with burnt oil and also allow you to check the gasket seal.
or you could try snaking a camera into the intake ports for a looksee.
3. If you do not have the milodon or equivalent lower tube seals installed you should. TUBE SEALS LINK
Even if you do have the seals installed, inspect the outside of the tubes where the O ring seal sits. i have found the tubes to be of very poor quality with lateral scratches and rippled sides.
Also check the ends of the tubes on both side of where the tube seals against the head for gouging etc.

My guess is #1 good luck and keep us posted