Brought Dart to shop to fix idling issue and car runs like s**t!
My ignition system is a mopar electronic distributor no vacuum advance with msd 6al box.
That's a REDFLAG right there.
I know yours is a 383, but I once had a 292/292/108 in my 367 and it liked a TON of idle-timing, But as I took timing away, it would eventually tick over at 700 and less, with a correctly adjusted Transfer-slot exposure.
My current 276/286/110 cam, which is only one size smaller that yours, will tick over at 550rpm, pulling itself along at a tic under 4mph,(Commando 4-speed) at 5* Idle-timing. I'm pretty sure your 383 can nearly match that.
The biggest deal IMO,is for you to prove the valves are closing, and not leaking, and that the cylinder pressure is fairly even. So to that end, I highly recommend both a LeakDown test AND a compression test.
When you do the latter, keep cranking until you get two consecutive about-same-pressure readings.
When you do the former, and if you get poor results; remove the valve gear and redo the test with the pistons at the bottom. Also, at this time, manually rotate the crank thru a couple to a few revolutions noting how hard it is to break and rotate it. Tight rings create a frightful amount of friction, making idling very hard.
The results of these three tests will probably point us to the next move.
The reason that the No-Vcan is a red flag is because at Part throttle, that cam will want a lotta lotta timing, and there is absolutely NO WAY the factory D can supply it. If you try to fudge it, your carb will idle waaaaaaaaaaaaay too far down the transfer slots, resulting in tip in sags, to outright afterfires, or even back-thru-the-carb lean missfires..
The more you retard the idle-timing, the further up the transfers, the throttle-blades will climb, reducing tip-in problems. Most carbs will want the accelerator pump system readjusted after significant changes in idle-speeds.
AJ's guide to Transfer Port Synchronization
