Wondering if anyone has a thorough knowledge of the operation of the electronic retard on a 70 383 with Holley carb. I installed a new vacuum advance unit and it seems to trap vacuum and keeps the advance around 10-12 degrees when at idle. It will only revert back to TDC if the vacuum line is pulled from the advance. Then the next time the throttle is opened it advances and stays that way again at idle. This obviously keeps the idle speed too high. It has 2 wires from the advance unit labeled ground and batt. The hot one ties into the engine wiring harness that is hot when the key is on and the groung is wired to the pigtail that comes off the carb idle adjuster screw. I can't lay my hands on the service manual at the moment and hoped maybe someone knows how it is supposed to operate.
Thanks for any help.