Harms Rebuilt '71 Thermoquad - Wondering Idle, Stalls when Put in Gear

4spdragtop said
Vacuum leak. If you use a spray bottle with water it should stumble at the leak.

Unless leak is below intake, bad gasket on lower part of port, pulling vacuum from crankcase.
that would require a smoke test, i know of no other way to determine if its leaking there.
like shaved heads and intake wasnt matched.