Bill, I need to ask someone this question: My stock '69 1/2 Camaro SS/RS valve cover bolts have a "D" on the head. Is this in any way significant when trying to keep everything stock? I can't find any mention of these "D" bolts anywhere. Probably a real minor issue, but my "mechanic thought he'd do me a favor and took the paint off with a wire wheel—and destroyed the threads. If the "D" matters I need to find a set. If not, I can find some "TW" bolts which are supposed to be correct. Just the fact that I can find no mention of the "D" makes me wonder.