For 1955 RD17 only -Here is Field Repair Kit p/n #277598 with instruction sheet #304683 info from Ed Sam (Thank you Ed). Took a quick look and it ADDS the baffle into the 1955 motors which was removed by th later mod. It also makes some changes on the bottom of the powerhead and the top of the exhaust leg. If I were working on an RD17 I would look this over and compare to the photos of the RD18 above before making the later mod changes as summarized by Chris_P above. As things are now we do not have the final written OMC mod/bulletin for the 1955/1956 RD17/18 motors.
