Maybe the compressor is the determining factor then.
Is hydrovac a brand name or a descriptive name?
Vacuum isn't used is it? I certainly don't know how they work.
Tonight I pulled the plugs squirted alittle oil down each cyl and thought I'd crank it with the plugs out. There was nothing. Not a click, no sound at all from the starter. If the engine was stuck I thought I'd hear something from the starter, but don't know because I've never tried turning over a stuck motor before. Tomorrow I'll try to turn it over by hand to find out if it is stuck. The battery is good. The headlights did come on, but somewhat slowly. I'll have one of my boys push the floor starter button while I watch it to see if that is working right too. Anything I'm missing?