Carb question stock 340

What kind of stall would you put on a stock 340? Also I was looking at 3.73 for gears but I don’t know much at all on the subject
Leave it alone. People are generous in spending your money.
My advice is spend the money on fixing what needs to be fixed and fuel for tuning.
Then see if you still want more acceleration or top speed or whatever.

Fix the belts if needed. Get the PCV and breatehr connected. Make sure the vapor lines are connected and open. With the after market carbs the bowls only vents into the air cleaner - so that one is simple. That leaves the fuel tank vent and and vapor lines to a charcoal can or something.

Tuning. Since its stock, it ought to be easy, just follow the book.
But with the 4779, there's a decent chance the distributor has been messed with or replaced.
If its factory, unmolested, then do it by the book and see how it goes when you adjust the idle fuel mix. If your satisfied, great. If its stinks, or dies when put in gear, or needs a high idle rpm, then the timing curve needs to be measured.
If its not factory unmolested, then the timing curve needs to be measured.
When you have graphed timing versus rpm, then you will know whether a smog curve with lots of fast advance above idle, or something more normal.
With a more normal curve, try an initial around 12* BTDC at 750 rpm.
With a smog curve, you'll have to compromise and use less initial until you modify the slots.