Update: Finally got time after the holidays to get out there and inject some air into the cylinders to see what I'm up against. I didn't even need to hold the engine from turning to feel the wind coming out the intake. The rockers are off, so the valves should be fully seated, right? Perhaps I didn't leave the air going long enough to get it going out the exhaust, but didn't feel or hear any there. I would have thought that the exhaust valves would have burned first, but whatever.