I purchased a 1972 C172L with the 180hp c/s prop conversion. There have been 3 owners since the conversion and some of the paper work was lost during the planes history since 1975 conversion in Canada. I need info re the Weight and Balance Data sheet that should have been with the plane. I know the present empty weight but don't know the change to max gross T O wt. other than by "hear say" which is not good enough. Perhaps the same info from an early model 172 with factory installed 180 hp c/s prop would be a great help. Any help greatly appreciated. Ian.