The mount in the pic is incorrect.The true original ones do not have the reinforcement welded to them. I have the true original mounts on my 07c 68 z with the original washers , nuts , and bolts. The number is 466 and you can find nos ones if you look . Corvettes used them also. The long bolt is fine thread and is shorter then the one in the pic. If you need anymore info email me. John Allouez Restorations