Originally Posted by
AquaNav77
As the new kid on the Hatteras Owners Dock, this is my introductory reply to a thread. The Cummins V8-300-M was the predecessor to the 903. As stated, it is the non turbo version of the VT8-370-M. Both of these engines were 785 cubes in displacement and both rated at 3000 RPM. At that time the Cummins 300 and the 8V53 were considered to be medium duty engines hence their high RPM. The Cummins 300 had over the 8V53 much quieter operation and better fuel consumption because of its 4 cycle nature. The Cummins engine was heavier than its DD counterpart and both were available with the Twin Disc 506 marine gears. The Cummins engine was also available with the Capitol gears. Longevity should be rougly the same and parts are expensive and sometimes difficult to locate for both. BTW, the Coast Guard never used the 785 cube engine. They started using Cummins engines in their patrol boats when the 903 came unto the market.
Jim