MerCruiser: Kit contains thermostat to replace #59137 and gaskets to replace #27-90556, #27-47510, #27-60208, and #27-48818-1. Fits the following engines: H.P. Beginning S/N Ending S/N 215 Ford 3040411 Up 225 GM 2399198 2694014 225/225S Ford 3385721 Up 228GM 4765100 6218461 230 GM IB 5907058 B522505 230/5.0L GM IB B522506 B525981 233 Ford 4173000 Up 250 GM 2314301 2639854 250 GM 4768000 4908849 255 Ford 3258728 Up 255 GM 4175500 Up 260 GM 4905520 6218461 260 GM IB 5907058 B522505 260/5.7L GM IB B522506 B525981 270 GM 2851074 3077735 280 GM 4176250 Up 320 GM EFI A543604 Up 325 GM 2313965 Up 330 GM 4623115 Up 330 GM W/BW 6083145 Up