Thanks Hardcore, what do you have? My original setup was a pair of 750 DP's with the air horns milled off, circle track floats, plugged power valves and jetted square. The carbs had been on my 446, 528 and then 572. They worked just fine on every combo. Apparently the 750's were big enough. I have gone to a few of the different sites on carb sizing and they all say in the 1250 to 1350 CFM range for a 572 @ 7400 RPM's and at 110% efficiency. I called Quick Fuel last week and was suggested two 850's. However, I wasn't to confident with the tech that I talked to. With every question I asked, he had to talk to someone else for an answer! What do you guys think?