I think as for the math and the formulas, the closer an engine is to stock, the closer the math is. 440s came right from Chrysler with carburetors in the 600CFM range and did just fine.
True but a 440 runs fine with manifolds but headers are better for power, bet it would run fine with a with a 2 bbl at a cost to power, put a 750/850 on a stock 440 picks up a decent amount of power. Bet if you put a 390 4 bbl on a 440 would work better than people would think, My cousin Late Model 372 pulls strong to near 7000 rpm with a 500 cfm 2 bbl, carbs are pretty flexible. People could use the formula but they would be short changing themselves in power especially in a performance situation but they would definitely not worry about over carbing :)
I think carbs should come with 3 cfm ratings the conservative 1.5 hg for stock and maybe add something like 1 hg for performance and 0.5 hg for race.
