Originally Posted by spinn
You saying the trans vacuum switch dumps the distributor vacuum podadvance signal?
I did some checking on that, and found i was wrong. The vac switch was manifold source fed, and low vacuum opened the switch circuit, disallowing lockup,so when in high gear and lockup, if applying throttle, and engine vacuum dropped, it would unlock to prevent chuggle, or driveline lashing (like when lugging the motor).
That would be on the 78 up models, when the 80 models came out with computer controlled carbs and dizzys, it then became an ECM function ( rpm, tps, and map sensor algorithm ) that controlled that part of the circuit.
So the vacuum switch setup is actually the best way to go, it is simple and needs no computer.
Good lookin out spinn.