[doug from upland]

I think the most Koufax had was 18 in one game. As I recall, at the time he had tied Bob Feller.

[pariah]

Kofax set a new record by strikingout 18 Giants, surpassing Feller's record of 17. I think it was in '59, before he had his big winning years. I remember hearing the game on the radio, and despite all the strikeouts, he darn near lost the game!

[Chu Gary]

"I think the most Koufax had was 18 in one game. As I recall, at the time he had tied Bob Feller."

Two pitchers have struck out more batters in a single game than their age at that time. For example, if Don Drysdale, a borderline pitcher IMHO, had been a thrower at age 17 and struck out 18, he would be one of the answers, but he didn't and he isn't.