Ok right now i have holley systemaxII heads. i don't know the rocker stud diameter. I bought vic jr heads. its rocker stud diameter is 7/16. it just dawned on me that if my holley heads are 3/8's then i'm going to have to buy new rockers. d'oh i don't want to do that. anyways does anyone know if the holley heads have a 7/16 or 3/8 rocker stud diameter? i searched holleys web site couldn't find an answer.