Do you mean where they connect to the engine or the mid pipe? If you mean the the ones that are connecting the header to the engine they are just screwed in. The two that connect the header to the mid pip i think are just studs.
yeah but I dont want to pull the motor for the headers when the stockers are sufficent. so worst case, I will drill it out and just put stainless bolt with lock washer and stop nut.