Mike, if you wind up having new oil pump gears machined, please have your machinist use either brass or phosphor bronze material. That's what the hot rod guys use for a replacement distributor gear when they convert to a steel camshaft (stock cams are cast iron, so a steel gear is OK there). I had a nice used roller cam for a Chevy V-8 that had the distributor gear area worn down to a sharp edge, all because some numb-nutz used a stock steel dist. gear on his dist. Brass or phosphor-bronze will "last forever".
Benny: the cryo- treatment affects the metal all the way through, just like heat treating does. A brother of my friend, Fred Young, up in the Sturgeon Bay, Wisc. area, owns a cryo- treatment company and specializes in bike engine parts. Racers cryo- everything: pistons, rods, cranks, piston pins - anything that can be heavily stressed.
