All for .370 lift and under ........

Using the correct 4bbl is likely to give better fuel economy than a factory 2bbl intake & carb.
You buy an Edel Perf [ not RPM ] or similar which has been optimised for the idle to 5500 rpm range. Compared to the factory low performance 2bbl intake, it will have more efficient runners/plenum that in itself will provide better economy.
The 2 bbl is a compromise. Throttle bores need to be large enough so that the higher rpms can be reached; this will compromise low speed/cruising economy. Using a small a small 4bbl of 450-500 cfm will have small primaries for better economy; if power is needed, the secondaries are there....