Re: Rebuiling? 1988 Johnson GT150 What fits??
Your GT has a lot of 175 hp parts on it already. Yours is probably making around 165 hp at the prop. Unless you change the midsection adapter, you will have to stick to the crossflow "flatback" engines, which were made up to 200 crank hp in the early 80's. Most will not run appreciably faster than what you already have. If you change the exh adapter, you could use the bubble back blocks which were 235 crank hp in the early years, 175 prop hp in the late 90's. A lot of the crossflow parts are interchangeable and it is easy to tweak the 150's for more hp. Higher compression heads, intake filler blocks, composite reeds would all help your GT perform better. Once you get any mods done and the engine is running, play with the setup. Proper engine height, setback and a hi-rake stainless prop will all help performance.
