what ? what is your output rpm ? WHat engine ? No boats run a 1:1, the casale is a reverser to run RH blades behind a T58. The GE SDG box is a 3.25:1 unit that many have run for years on T58s, they are hard to kill. WIll give you a 6200 rpm output behind a good engine and 140 Mph in a good hull. The last one I installed we had made in NZ but it was for more hp ( 3000 )