Dom, every engine is different. I had my Dominator on a 650 cammed 440 with an M1 and adapter. One of the best in this area, Dale Cubic, set it for that engine. I then put the same carb on my 650 roller cammed Hemi using a 4500 intake. I thought it ran great, until Carburator Joe from APD, as mentioned by Rickster, totally went through it again. After getting a baseline of 505 RWHP, I gave them the carb. Changing nothing but bolting on the new carb, I gained a real world 30 RWHP. Then Vic(DIscoQuik), fine-tuned it for the street. It idles @875, and still runs 10.80's. I'd listen to your carb guy, and let him "tinker" with it. $400 is the going rate, I believe, for quality work. PM AndyF. He's the resident tinkerer and knows what works. I think he tunes in his sleep..