I'm pretty sure these are grade 8 bolts, they have these markings on them that I've never seen. And the head of the bolt is "dished" slightly, maybe 1/16" deep. They were holding the leaf springs to the axle on the front of my 33. I'm positive they aren't original, but I've never seen this marking before, kinda neat! I also found a few smaller bolts on the engine that have these markings. Every single bolt on the truck is grade 8 (but with the usual grade 8 markings), so I'm guessing these are grade 8 as well Anyone know what it means, or seen it before? If nobody knows, I'm just going to assume they are alien hardware from a space ship. .