i am looking at a 1959 evinrude 50hp that has an extension sandwiched between the lower and upper gear case to make it a long shaft. can it be removed to make it a short shaft without having to find some other parts? specifically, i'm wondering about the vertical shaft. is there some kind of an extension piece that can be removed to make it shorter? also, any problems i should look out for with this particular motor? Thanks again, dave