I have a 283 i just built, Basically stock except for cam and roller tip rockers. I put a crane cam .502/.502, 294/294 duration in it and found the WCFB carb does not work due to lack of manifold vacuum to hold down the metering rods.(385 CFM) I bolted on a 4GC carb and it runs a bit better. I can get it to idle correctly under 1200 RPMs. The idle screw is turned to the point the idle transfer slot is uncoverd and the boosters start to pull fuel . Its originally from a 348 engine, so CFM isnt an issue. The cam was intended for higher RPM(3200-6400) in a stock car. I need some input on using a 4 GC on this motor. OR should I change the intake to use a AFB or Q-jet? Its a semi-stock 57 chevy...I didnt want to modify the car too much under the hood.