[cadillac512]

If the vacuum is being checked while cranking (won't start so it's not running) it'll be low for sure, and will drop to zero when holding the throttle open. That won't cause it to not start. A shot of starting fluid is a good idea since that rules out the fuel system.

You can check timing with a timing light while cranking if you want to verify timing. Use a 12v battery to power the timing light if necessary.