Sounds like a lot of work to cure an idle stumble, and if the gear is installed correctly the first time, it's a moot point. I believe the modification to make the gear a slip fit and bolt it on is probably a better way to solve the problem. Some of the nitpicking we hobbyists do these days would have caused a flat rate mechanic to get fired back when these engines were in daily drivers. Changing a timing gear was a 3 to 4 hour job when I was doing flat rate work, and that included dropping the oil pan to get to those two bottom timing cover bolts. If a line mechanic couldn't change a timing gear before lunch, he probably wouldn't have a job the next day. I seriously doubt that those guys got picky about the end play on the cam.
Jerry
