what would be your diagnosis?????
3) Did you change the PCV to one that closes down at a lower vacuum? The stock Mopar PCV's will not close down properly with these low vacuum levels. The 'idling up' when you close off the PCV hose is a clear indication that there is too much air coming in via the PCV at idle.You NEED to take care of 2 and 3 above or you are chasing your tail.
I have found that cams of this size, once the T-port sync is set and the timing is optimized,idle-vacuum comes up to where the PCV leakage actually helps with the idle-air bypass. SO FAR, in my experience,the "leaky" PCV can easily be compensated for with the secondary cracking screw. If however the PCV is directly sent into the intake,into the booster tap between runners 7 and 8, that makes trouble. The PCV has to be sent to the carb base for some semblance of reasonable mixture distribution.
As the OP describes the way his is working, is exactly the way I have experienced, and have always been able to make it work, SO FAR.And with any common sbm type 90* PCV. In fact, I use that PCV circuit to help establish the initial amount of secondary cracking, that I will dial in on the upside-down carb on my bench.
Now, I will say that on some combos, and without 4-corner idle,I have run into idle issues with the back running lean from the secondary cracking. And in those cases I sent a little air directly in through the primary plates. Nobody wants to hear that, but I do what I gotta do, to make the engine happy.Some guys compensate with excessive idle timing. That works, but for a streeter,IMO is a poor solution and causes other issues.
So, nm9, I'm not trying to minimize your experiences, only adding mine.
So how about that T-port sync?