The marine and railroad versions were 1200 rpm. but, but , but are the loudest, loudest, loudest gen sets on the planet! the gen heads are the best! Most are 12 lead and can give 208, 220, 3 phase newer ones deliver 120/240 single phase as well. some have been knowned to run after being soaked under water. Even salt water!. expect to pay $3000.00 + for a new 1200 rpm 120/240 Delco head.