RE: Gms Engines?
The choice is yours. People argue the merits of ringed or ABC/ABN engines all day
The Tower engines are ABC as is the smaller GMS engines. The GMS 61 and bigger are ringed.
ST 40 is ringed, 45 is ABC, The 51 is ringed. The 61 can be either ringed or ABC. The ST 75 and larger are ringed