Help ID Motor: Need Starter

[adis]

I am swapping a carbed Vortec 5.7 for my ‘80 K30s 350. The staggered 9-tooth starter from the 350 doesn’t seem to work on the 168 tooth 5.7 flex plate. The pinion gear hits and grinds. Tried shimming every which way, no luck. The 5.7 has holes for both straight and staggered starters. Does anyone know the correct starter for this motor (part number).

It’s possible I dont have the motor identified correctly. It’s an 880 casting with the following stamped code: K0123FKA. It’s a Vortec just don’t know the year and application. Any help getting the right starter is appreciated - mark