[Woodz428]

Vacuum problem sounds like timing,either ignition or cam. Or a too radical cam. But with the overheating as well, I'd be leaning toward timing. If the overheating was occuring separately, I'd say pop off the thermostat housing and look under the thermostat to make sure someone hasn't remove the round diverter that should be there. You didn't mention any plug readings or any other data that would help in tracking the problem down, idle screw settings, throttle plate position,jetting etc.