223's are the Ugly Step-child's of the XO World, they got less cubes than a GMC, and less speed equipment. But they do have a more modern head than the ancient GMC's, said to flow as well as a chevy, well, at least as well as a Y-Block. And as you said, seems to have a bit too much carb. We are running a 600 on our race 278 (or so) race motor, and when we ran the Brew 102 with a stock 223 we ran a 450(?) two barrel which really woke up the motor after running a 600 early on.