Actually if the airflow is too sluggish from the carb being too large the AF might be too lean but thats a non issue for you here as the 600 will be perfect & no need (for me) to confuse the issue. For the cam I would Google it & find someone credible recommendations (car owners) so you can get the right cam the first time & I would definitely go conservative (when a cam co gives me a recommendation I go 2 or 3 sizes less! (even with Dave Hughes)