The Edelbrock 750 has 1 major problem and that is the length of the primary booster is shorter than it should be. Any early pre Carter/FM 750 will have the correct longer booster if you want to compare.
From memory when i compared the both the longer booster activated the primary flow sooner.
Heres an Eddie 1407 thread at Speedtalk:
Edelbrock 1407I would look to the NSS guys for guidance as thats their bread and butter.
Also heres a write up from Dan Dvorak on AFB's. Well worth the download price $1 for what he knows.
Carburetion: A maximum performance treatise Hope this helps
Hysteric
