Poor idle and off-idle performance after distributor swap

67Dart273 said
Most any larger than stock cam needs more than 12BTC, but has that changed between the two distributors?

Are you running manifold vacuum advance or "ported" vacuum? (I run ported, period)

Ported, absolutely. Ran 12btdc on old distributor with 25 mech. New distributor has 20 mech, so I bumped initial up to 16. Will test on hotter day giving it more advance.

TT5.9mag said
As always with an edlebrock, especially after it’s been rebuilt, check and set the float levels so they are dead nuts. Make sure you have zero vacuum leaks of any kind. As you’ve said, disconnect the vcan and disregard it for initial tuning. Bring it in later and use ported vacuum. The statement “timing was jumping all over the place” worries me. It should be stone cold steady regardless of carb settings. Sounds to me like you have multiple issues that need to be systematically worked through.

The bouncing timing mark worried me too, but it the car runs well now and still has the bouncing timing mark. I wonder if it is my inova dial-back timing light, but anything past 12btdc disappears under the water pump/timing cover so I have no other way of verifying. The bounce does appear to get more pronounced the more I advance timing on the light/gun. Before the rebuild, I installed the V-6 timing chain tensioner and my timing was rock solid using a non-dial back light, but it was also at 12. I hope the machine shop that rebuilt the motor used the tensioner, oil dripper tab and hollow bolt, oil slinger, etc. but its not worth tearing down the frontend just to look. Might be a winter project in conjunction with an aluminum water pump housing.