CFM = (rpm x displacement)/3456 ( 4,000 rpm * 360 cubic inches ) / 3456 = 416.67 CFM at peak torque on an AMC 360 you only "need": ( 1,700 rpm * 360 cubic inches ) / 3456 = 177 CFM So the 290 CFM carb that comes stock on the '80's vintage Wagoneers is ok... But, if you're building an engine to run at 6,000 rpm... then you'd need: ( 6,000 rpm * 360 cubic inches ) / 3456 = 625 CFM