GM has a half-dozen PMGR starter designs. Some of those designs fit SBC and BBC; and may have 153-tooth, or 168-tooth flywheel/flexplate housings.
In general, if the starter bolts are directly across from each other, it's a small, 153-tooth starter housing. If the bolts are at a diagonal from each other, it's for the bigger 168-tooth ring gear.
Back when Remy was still a viable concern, they issued a bulletin about upgrading from the old direct-drive starters to the PG260-series of PMGR "mini-starters". See attachment below. Both of my trucks have the PG260 starters. The '97 K2500 7.4L probably came with a PG260; the '88 K1500 5.7L was converted years ago.
I brutalized the OEM direct-drive heat shield from the '88 direct-drive starter to fit the PG260; and it's been fine ever since.
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NOTE: the white wire on the solenoid of the PG260 starter was intended for use with a "Ford solenoid" on the fender, to eliminate problems with insufficient power on the purple wire to the "S" terminal--a common problem with older GM vehicles. However, that "Ford solenoid" trick DOES NOT WORK on the PG260; it causes the starter to drag and grind when the key is released from "Start" back to "Run". The white wire was eliminated after about a week, and the Ford solenoid was removed in favor of the OEM wiring method.
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