400 cfm AFB?

Hummm... I thought the smallest AFB was rated at 500 cfm. All the Pontiac's I saw had 625's on them but you could ask lead69 as he knows Poncho's real good. The early GM's used the WCFB (Will Carter four barrel) and I think it was smaller but not sure on the exact size. It was last used around 65 if I remember right, then they switched to the lighter AFB (aluminum four barrel).

BTW: 500 AFB's were used on some lower perf. mid 60's Mopars. I had a 66 Newport with a 383 that had the 500 AFB on it. It used the narrow bolt pattern.