Need help tuning Quickfuel carb

I’ve experimented with the timing, I’ve had it as low as 32 and as high as 36, I’ve tried different initial timing settings from 14-20.
I’ve had the carburetor completely apart and sprayed every passage out with carb cleaner and compressed air.
Never found anything un-usual.
I have noticed that some days it’s not as severe as other days which is really strange.
Another thing I noticed was my voltage regulator was going out and when the voltmeter in the truck would peg at 18v the missfire would get better.
I’ve also noticed that sometimes if I step on it really hard and then back off it and maintain a steady speed it will clear up for a little bit.
I don’t think it’s a vacuum leak, why would a vacuum leak be causing two plugs to carbon foul?
I’ve always been under the impression vacuum leaks make engine run leaner not richer, plus I have checked for vacuum leaks around the intake and carburetor and can’t find any.
My intake manifold gasket is fairly new maybe 5k miles on it and my carb gaskets are brand new cause I just had the carb off last weekend.
This msd box I’m running now is the second cd ignition box I’ve tried, originally I had a crane cams hi-6 cd box and I thought something may be wrong with it, so I bought this msd box and no change.
So this is the second ignition that’s been on the truck, I’ve literally tried swapping every last piece on the ignition And it hasn’t done anything at all.
I’m very certain it’s not ignition, it’s ether fuel or a mechanical issue in the heads.
But the good compression numbers are what’s throwing me off and the steady vacuum at idle.
Nothing has indicated an issue mechanical wise, I don’t hear any strange noises in the valve train, i don’t see anytning when I pull the valve covers, I’ve even let it idle with the valve covers off and everything appears to be moving as it should be.
This is a real stumper, I’ve been fighting this for months with no luck at all.
The only two other things I could do at this point is replace the heads or replace the carburetor.
I just don’t want to spend that kind of money without knowing for sure what is causing the problem.
Like I said this carburetor is brand new, very low miles on the carb maybe 5k miles.
A guy I’ve been talking to over on moparts is who steered me in the direction of an issue with my carburetor or my carburetor tune.
He only lives a couple of hours away from me and has a shop, I’m getting frustrated enough with this missfire that I Am seriously considering taking it up to him to check out.
Cause I’m just not seeing anything and it’s very frustrating.
I was thinking maybe a valve spring but I can’t see one that’s broken.
But the missfire is very prounounced like it misses hard and you can feel it in the cab of the truck through the floor and the steering wheel everytime the engine fires on the cylinders that are missing.
I mean it misses hard enough that for the longest time I thought it was a drivetrain issue or an engine balance issue.
But when I’m in park I can bring the rpm up to 2500 and it will start missing and you can hear it through the exhaust.