There is a lot of confusion about the 192 and 250 Small blowers, maybe this will help:
As of 2021 the only thing that a 192 fits is a SB Chevy with 23 degree heads – (We are looking at SB Ford as a possibility)
The 250 Blower (Different animal) is made for BB Chevy w 23 degree heads and LS engines – all of them (We are looking at SB Fords as a possibility)
192 means it displaces 192 cu in of air, and moves that much each time it rotates.
250 means it displaces 250 cu in of air, and moves that much each time it rotates.
The two blowers do NOT interchange on different manifolds.
The 250 Blower does share the mount base with the 250 Blower on a Merc Cruiser Marine engine.
They were both designed for the street, but have successfully found their way onto Race engines, but they are not big blowers and will not make big amounts of boost.