Hershiser was 1988. Pretty sick year but I give the edge to Pedro.
Agreed. Hershiser's last 9 starts that year:
82 IP, 8 complete games, 57 K, 15 BB, 48 hits allowed, 4 R (all earned), 0.44 ERA, .403 OPS against
Pretty amazing stretch.
Pedro was putting up batshit insane K/BB ratios. Hell, only 5.3 hits per 9 IP, 4th best all-time among single seasons.