Are they special?? I dont find any markings. So are they like a grade 2? You can drill them, we broke 5 off in the heads. I'm thinking of replacing them with either a grade 2 or a 5 with never sieze. What do you guys think? Bill
I would most deffinitly go with a hardened bolt [ grade 8 ] it will last without breaking again! Take it from an old exhaust guy!
I thought about 8's but was afraid of ever having them break again. I will take your advice and go with them. Thanks
oh man, I had the same problem, we also had 5 break off in my heads. I don't think they're grade 2... more like grade V, V for velveeta. I was so angry by then I just let the machine shop deal with it. $25 per broken bolt was worth it.
I bought an ARP stainless engine bolt kit for my 352. Unfortunately none of the exhaust bolts would fit even after chasing the threads with a tap. I had to chase all of the threads of the new bolts with a die or they would never fit. Way too snug. I used anti-sieze when they finally went in. Over all though I think they were a good investment.
I used anti seize and then for the top ones drilled through the casting and used brass nuts both sides.
I broke them all off on an old 68 pickup and used a button tip on the Victor to blow them out. Then used grade 8 5/16 bolts with nuts on the back. Kinda ugly but you will never have the problem again.
on my 390 they all came out!haha..but on my 352 they didnt.i just welded a nut to the broken stud ,filled the nut in with weld,then heated the ear of the head,and turned them out.zero thread damage.didnt even have to chase em.that method seems to work every time.some were even broken flush,or below the head surface.and for the ones not on an ear,just heat the nut and stud.i weld em hot with low wire speed and stitch till it's done.
The Jalopy Journal
