Originally posted by 327,JET
It sounds like a problem with the dist. The dist. is over advancing the timing. There should be a limit pin or ridge that prevents that. Maybe it's missing or broken off . I you continue with that much advance timing , thing's could go real bad real quick. You could alway's get a conversion kit with a magnetic pickup at the very least . It's just one less thing to worry about.

I don't think he has a problem with the distributor.
Everything is working as it should if he shot the timing - and it appears he did - with the vacuum advance connected.

If the vacuum was shot with the vacuum advance disconnected and the mechanical advance was allowing that much advance he'd hear some serious knocking once the engine was under load and the rpm's were up a bit.

Engines like - and need - a lot of advance at light throttle settings.
Especially so at idle.
Most times, running sans vacuum advance or using ported vacuum (tapped above the throttle blades) will lead to overheating at idle and in summer traffic.

Far as I know the electronic conversion kits don't change the timing characteristics of the distributor.