I've been running the "recommended" 390cfm Holley for about a year now and overall it has worked quite well. The engine runs well and starts within a couple seconds whether it is 100 or 20 degrees outside. The only thing don't like is that when the choke/fast idle are set up for winter use and there is a warm day the car will fast idle for an unnecessarily long time. Not a real problem, just a slight annoyance sometimes.