82Waggy Heading says it all. Would provide for a complete anti-walk kit when used with the Rollmaster torrington bearing timing set.
jeepsr4ever The head of the cam retaining bolt is VERY close to the timing cover...VERY close. A cam button has been known to eat a hole in the timing cover. The only time you need a cam button/anti walk is when you are running a camshaft that isnt retained by the lifters. You can easily fab up a small plate that has a hole in it large enough for the snout of the camshaft and use a torrington bearing.
82Waggy OK I bring it up because of the three engines I've torn down all had been grinding the dizzy gear retaining bolt into the timing cover. Maybe the solution is a scrub plate mounted to the cover with an oval head retaining bolt?
82Waggy Here is a cam anti-walk bushing from AM Racing in Canada. http://www.amracing.com/parts/b006/b006.html