change jets or increase carb size

[crazypete]

You could attack the problem scientifically by inserting an oxygen sensor attached to an A/F guage. Thats how I tune my holley. In all honesty, my plugs always look white even when I am running super rich, so I would heartily recommend a sensor instead of the plug reading method.

A 625 cfm seems a bit low in my opinion but I dont think its really hurting you that much. If the car runs well and doesnt overheat, then I dont think there is much of a problem..heck, you are saving yourself some gas. What jets/powervalve/shooter/cam are you using? I am using 68/70's,8.5 pv, .28 shooter and the base cam on my 670 street avenger vacuum secondary to run my little 302.

I love holleys for their adjustability. I will never fuel inject again. I also had a lean situation that was affecting idle and I alleviated this by spray carb cleaner into the fuelbowl and letting the carb clean itself from the inside.

Good luck!