For things like shock towers, the factory should have used grade 8 bolts. Reason they didn't has to do with the really not so perfect 1/8" metal they used for the frame itself. This thin metal can warp, warble and cause a failure so easily. By having ANY space between a bolt and the frame, you can add to this effect. They ruled out this possibility by using rivets. Rivets are the reason they were able to get away with 1/8" frame material. By completely and totally filling the hole so completely it effectively makes the connection as solid as if it were welded (almost), they got away with it. Gus always does an excellent job.. expect nothing else. If I were replacing shock towers, they would get grade 8 bolts. Every shock mount I have ever seen from that era is damaged in some way due to the stresses the factory didn't expect. I weld them up all the time. It wasn't one of the engineers more shining moments. All they should have done was make the shock tower material 5/32 or so. They didn't expect the dang truck to last 100 years! The frame is grade 2 mild steel as well as every part on the frame including the rivets. That really puts you at the mercy of the design.
