My 1973 C150L has been converted to a C150/150 using an Aircraft Conversion Technologies STC. I have flown a 150M that had this power upgrade and I believe it had better rudder pedal balance in flight than my C150L/150. Cessna increased the height of the fin/rudder of the C150M by 6 inches relative to the earlier C150L in 1975.This probably improved the rudder balance of that aircraft. I would like to change the fin/rudder on my C150L to the larger C150M size using parts from a reputable salvage company. I have been told that this can only be done by using an STC prepared specifically to cover this change. Does anyone know of an STC that has been prepared  for this purpose and if I could get access to it and use it?