Eric - Bulletin 1000 (1100b-4407 from Nick's site) on  PDF Page 15, shows the 71974, 7 tooth pinion used on an A.C. governed motor with a 74106, 35 tooth gear.

A gear chart I have shows a 7 tooth pinion, 78510 with a 30 tooth gear, 78509 for 7.42 60 speed operation with an 1800 RPM sync motor.

Tom  N3CRK