ARP 3/8 x 1" bolts. Wired, lockwasher, and baptized.

Still breaking.

The broken bolts came out by hand but damn do I need to fab a brace for this Pfab top mount? I dont know what hardware is going to be stronger than the ARP?

 

I have never had good luck with threaded flanges. I drill the threads out and use grade 8 bolts and nuts with a washer and lock washer on top and bottom.

 

Ceramic coat INSIDE and OUT. Problems will be gone.

I can run regular home depot hardware and have no problems now.

 

they have grade 8 bolts at home depot just sayin

 

Full Race sells a stud and nut kit I will be running, supposed to work well, but it's pricey so well see if it's worthwhile

 

i'm running the full race nuts and studs, no issues so far

 

Running lowes hardware, no issues for 30k miles

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Several of the bolts look to be grade 5 bolts (indicated by the markings in the heads) it is hard to tell from my phone but I would check that out.

Secondly the material selection is key also. I would recommend using a standard mild steel. You want the material to be ductile and have a thermal expansion to match the manifold flanges. If you can get close ups of the surfaces the sheared you may be able to get a better idea of why it failed by doing a bit of searching online.

 

ceramic coating works wonders. My top mount pfab manifold is ceramic coated, as well as the turbo hot side. Never had a stud issue.