cangus wrote:How do you tell the difference betwen a 1988 MC18 engine and a 1989 MC18 engine?

Hi i have checked my parts book for you and as RobH has said yours is a R2j Model motor. This will mean it will have the 1988 crank installed and will have a seperate center seal and bearing setup. Unfortunately you cant fit a modified later crank into these cases as the center seal and bearing are different so you will either have replace the whole bottom end for a later model where cranks are still available or find a very good machine/engineering shop to rebuild the crank for you. Using a late bottom end will be the best idea as cranks are available for these and hopefully will be for while yet but new cranks are no longer available for the R2j model. Hope this helps fella.