I got some original 67 battery hold down bolts. In comparing them with the AMK replacements you can see the replacements are 5/16 longer. At a MCA judges meeting Bob Gains had one of his original Autolite batteries. We sat it next to the current reproduction and noted the reproduction was about 5/16 shorter. If you compare a original battery tray with a reproduction you can see that the cuts for the J bolts are higher. All of this can add up to 3/4 of an inch extra bolt thread.