If you go 500 cfm. make sure you have a Holley and not an autolite carb. The autolite carbs are a pain in the #$$. The Holley is much easier to tune. Power valves with age could cause them to go. One other thing I forgot to mention was if a piece of dirt or a hair or something gets in the needle and seat, it could cause your rich problem too!! Check your needle and seat out. Depending on your motor, a 500 cfm may not be enough. I had one on my '79 driver and changed to a Holley 600 (1850 vacuum seconday) put 68 jets in it and man what a diference. Your power valve gasket may be in just barely off center as well. Check these things out. Good Luck!!
|