Remove the carb and reset the secondary throttle blades so they are almost closed. A 3310 is a vacuum secondary carb and normal '2 corner' idle. The secondary transfer slots are high up in the bore. If they are showing .030 below the blade - it is way too far open. That would be both a vac leak and a source of fuel.

,030" on the primaries is a starting point. Anything from .020 to .040 should be OK. While the carb is off, write down the turns out on the screw so you'll know how much they are exposed when you are fiddling with it.

If you see fuel dripping out the boosters when you shut it off, the fuel levels in the bowls are still too high.
If not, then excess fuel at idle could be the bowl leaking through a ruptured PV diagrapm into the manifold.

Not sure what you're trying to do with burning oil and smoke but the rubber diaphrams may not have liked that.

Timing. Initial Timing should always be measured with the vacuum line capped or plugged regardless of whether its using ported or manifold. Thats true for stock or modified. 12*BTC at 500 rpm is good starting point for a stock or close to stock engine.

Buy an old copy of Urich and Fisher's Holley Carburetors and Manifolds Lots of good illustrations explanations in there and things will more sense. Almost as good is Urich's little Holley 4150/60 book. Both are available used for cheap.

I thought some of this sounded familiar. Some of this may be a repeat, but that's OK.
https://board.moparts.org/ubbthreads/ubbt...tml#Post2287841