Reply to "Holley 650"

One trick to avoid having to open the primary throttles up so much that they go above the transfer slot on a wild cam engine, is to drill a 2mm hole in each primary throttle plate. I must say though that it's rare that it's necessary if the carb and ignition is properly adjusted. The cam has to be very wild. And as Holley says, if you can get the extra air needed to get a good idle via the secondaries, that's a better method (and reversable).