Posted by Rob Steller on September 22, 2000 at 20:57:57:
In Reply to: Grade 5 or Grade 8?? posted by Tex on September 22, 2000 at 08:35:50:
I've never heard of the tractor bolt title, but I'm on the west coast, so what do I know! Yes the the grade 8 bolts are stronger, about 150,000 PSI steel as I remember, and grade 5 is about 100,00 PSI. Grade 5 bolts are usually identified by three radial hash marks on the head of the bolt, Grade 8 by 6 radial marks. Grade eight are used in most high stress locations such as rod, head, and flywheel bolts, as well as in differentials (I think old PW ring gears were not held by Grade 8). Most other structural bolts on the dodges were Grade 5, and that's what I'd use for your motor mount. I won't even use Grade 2 (standard unmarked bolts) for anything, as the cost for Grade 5 over Grade 2 is so low, and they don't break when you tighten them! Good Luck! Rob