Remove a small manifold vacuum hose, like the one going to the choke pull-off. The engine RPM should increase slightly. Turn the speed screw back down idle and look for both nozzle drip and more sensitivity with the mixture screws.
How much vacuum is it making at 750rpms?
While you are idle tuning I'd also loosen up the distributor and add some initial timing. If it gets really happy with that deal the VA can be employed via manifold vacuum at idle to offset all the negatives.
This will simply involve installing a VA with a lighter spring adding the amount of timing to get the initial where your engine likes it at idle speed. Personally I'm NOT a big fan of that deal when the real fix is about a full point more compression, 10 degrees less duration, or same cam moved out to a wider LSA, or combinations of all three.
In any case it appears the carb now has sufficient idle fuel, so just a few more tweaks and you'll be good to go........
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73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile),
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