IH Farmall 656 gas/ IH 240 Utility/ 2, Super C Farmalls/ 2, Farmall A's/ Farmall BN/McCormick-Deering OS-6/McCormick-Deering O-4/ '36 Farmall F-12/ 480 Case hoe. '65 Ford 2000 3 cyl., 4 spd. w/3 spd Aux. Trans
Here is a youtube video where they are adjusting the valves on an M. Your 100's valves are adjusted the same way, but should be set at .014 hot. If adjusted at this clearance when cold, things tend to expand when it gets hot, and reduces the clearance. Better to have them a smidge loose than tight, to prevent buring a valve. And by a smidge, I mean just where the feeler gauge slides through with little resistance.