I'm 3 steps behind you guys. Sorry.
A stovebolt engine breathes like a neck being strangled. Making the mouth wider (bigger carburetor) doesn't make breathing better.
I get that point. The optimum is to somehow match (+/-) the carburetor to the restriction or reduce the restriction or use force (turbocharge)?
Back to the YF. Jon said that Carter tested the YF's A/F at various vacuum steps.
Turn back time.
GM engine designers asks Carter carburetor designers to build a carburetor for them.
GM would have to provide Carter a graph of actual measured engine vacuum steps and the desired A/F ratio for each step?
Carter would design idle ports, low speed jet and more importantly a custom fuel metering to meet GM's requirement.
How did GM measure engine vacuum without a carburetor attached?
A big variable speed DC motor connected to the driveshaft and a Pitot Tube inserted into the intake throat opening?
