Had a 1987 caracal with a 150 Gt by Johnson. 17″2″ boat, a drivers boat!!! ran a solid 70 with me and my tackle and a load of fuel. loved that boat only shortcoming was a nose that was low to the water, so with me 280# larger waves came over the nose. I ran an early worked 26 raker that was very fast and my every day prop was a 4 blade 26 predator ( great prop). I f your engine runs strong I think they liked the rpm so I would say a 24 or 26 trophy would be a good place to start . Dont buy the prop without testing it first! Most prop shops will let you drive and decide as long as you dont ding them up. Irv