Thumpr cam crap

10"@1000 with 36* idle-timing means something is seriously mechanically wrong.Or the firing order is out.
My guess is the intakes are not closing properly or she's sucking air somewhere other than the carb, or both. Yeah probably both.
If you decked the block to get a zero deck, "occasionally" , the machining gets out of whack and the intake sucks air on the valley side. To check for this, put a vacuum gauge on the dipstick tube, flip the PCV out of the VC (you do have a PCV right), and seal all openings into the crankcase; then start her up and watch the vacuum gauge. Got vacuum? Pull the intake and get it machined to fit. If you are lucky, it will just need the bolt-holes slotted a tad.
While the intake is off, you can check where split overlap occurs; and all your lifter preloads.
After that,or if no vacuum in the valley, then I would do a leakdown test.