In the process of installing my new ZZ4 motor. Never really looked under the hood of my truck as I was building it up so far but when I pulled the old engine, I noticed it had an edelbrok manifold and a quadrajet carb on it. The carb has a sticker on it that says "rebuilt by Holley" and I wondered if Holley ever sold rebuilt quadrajets? My real question is how do I identify which model I have, ie, the CFM of the carb to determine whether it is big enough for my new motor? Aren't there like two or three different sized quadrajets like a 600, a 750 and something else? The ZZ4 is about 355 horsepower. Does anyone know what CFM would be necessary for the engine. I would rather spend a little rebuilding this one than spend a lot buying a new one.