Correct. Had a ModMan with a Carter AFB off of my 318. I believe it was 625 cfm if I remember the numbers correctly. Cruised fine, but had the same nasty full throttle bog that I believe you were fighting. Traded a buddy for a Holley, but it was still a vacuum secondary and the linkage hit the top plate without a spacer, so I never did run it. Was getting ready to buy a new one, but found my MS2 deal first.