I ran KB107's .040 over with a 271/284 duration 484/485 cam with 587 heads shaved to 60 CC's otherwise completely stock heads.(no porting or even 3 angle valve job), not even balanced. Hooker headers and 4.3 gears. Ran consistent 11.7's. Put on a set of Hughes stage 1 heads and Hughes cam and ran consistent low 11.40's, dipping into the the 11.30's. Still no aftermarket balance. Ran that motor for several years and then sold the car.
Put on a set of Hughes stage 1 heads and Hughes cam and ran consistent low 11.40's, dipping into the the 11.30's. Still no aftermarket balance. Ran that motor for several years and then sold the car.