It is a late 80's 175 IMO....from '76 till '79-ish they ran direct wired stator, trigger, and coils with screw & eyelet connectors to the packs. Just like the Merc 260's/Drags. In '85 they went to Net horsepower so the 235 turned into a 175 but it is identical internally. Don't see a ton of the later X-Flows after the Loopers came out! Wiseco's in an X-Flow are super dense & heavy and do need some extra clearance in the motor. I wouldn't be afraid of upping the jetting & running more conservative timing until you get a bunch of heat cycles & 10+ hrs on her