what size are bolts for header on gs

[sdsdsd]

Hey guys, i was going to order some bolts for my header, i might not get the dealer ones b/c a buddy of mine said they can get some that won't loosen after i put on the new header but i need to know the size for the bolts that i need. do you guys know off hand what size they are?

sdsdsd thanks

 

[kamakazy59]

when i changed my exhuast headers there were like 4 different kinds i would not recomend any thing else than stock or new stock becuz my bolts ranged from 10mm to 12mm deep socket , 12mm , and the lengths of the bolts are also different.