Very generally, its going to be effected like this:
The idle to part throttle works on the pressure difference between atmosphere and the intake. That is, manifold vacuum. A cam with significant valve overlap for the displacement will have less manifold vacuum at idle. The larger the primary throttles, the more difficult it is to get the vacuum signal needed. So for that, and the exhaust reversion, need to set the idle fueling to address that.
The main circuit works on pressure difference created by the air velocity going through the boosters. The slower the velocity, the less the pressure difference and therefore the main air bleed and jets may need to be adjusted when using a larger venturi and booster for a given size engine and volumetric effeciency.
What you can do is get a copy (used) of Urich & Fisher's
Holley Carburetor's and Manifolds to have good reference on all the basics, what the passages do, etc. Then if you're up for it, get set of micro-drills and full set of the normal size numbered drills. Use the shank ends to measure and write down all of the restrictions.* The main jets are marked by flow, so no need to measure. Then you'll know its clean, gaskets are good, the floats are at a good starting point, and you'll know what its got inside.
Adjust the throttle position for something between .020 and .040". Write down how many turns this took because when you start the fresh engine, you may crank this up to whatever is needed to keep the engine running at break in rpm. But then you need to bring it back down to something between those numbers to start tuning.
*example of a nicely done table of Holley internal air and fuel restrictions here:
Mild Ford 289 Tune | '37 Pickup Cruiser - racingfuelsystems.myfunforum.org These will make more sense later after reading about the carb circuits work. Chrysler did some booklets on how carburetors work, you can find them on-line at
www.Imperialclub.org but I think Urich is the easiest and clearest for 4150s.
