I run a 600 holley list 6009 on a streetmaster intake on my 318. Am running manifolds and stock 340 cam. Pulls realy hard to about 5600 but will go to 6000 no problem. I suspect you may be running a bit lean, I had to jet up a couple of numbers from 60-62 to get rid of part throtle surging as the 6009 is an old emissions carb. With headers and a cam I think I would start around 64 on jetting and read the plugs and see what they look like. Holleys are realy simple carbs and very easy to tune.