well them are bad about pulling the rocker studs out..i had a SBChevy Heads and i had 3 studs came out and striped it out and broke it around where the studs go..Me my self i wouldnt get them cause they are junk and not to make u mad but i will never own another set..But now if you wanted to drive them on the street and not turn alot of RPM then they will be good for that..but as far as racing i would stay away from them..But thats me..Its up to you on if u want them or not..