Chris C.-
Let's see if I beat Kraig or not. The 38" rectangular, timed deck with two blades was used on the '61 to '63 Original and very early 70/100. The 38" and 42" "Cast Iron end" decks with cast iron corners and three blades were used on the 70/100 and early 71,102/122/123. They'll fit all NF tractors with the right mule drive/subframe combination. Next came the 38",42", and 48" "stamped end" decks that had stamped metal ends and three blades, with the outer two being smaller than the middle blade, just like the earlier "cast end" decks. These were used on the later (I think) 71, 102/122/123 through the middle of the 86, 1x8/9 series of wideframes. The mounting was changed from "pin on" with clevis pins to the "quick attach" system starting with the 72, 1x4/5. All of the stamped end decks will work on both NF and WF tractors with the right subframe, mule drive, and attachment style combination. Next came the 44" and 50" decks, starting at the end of the 86, 1x8/9 series in 1974 or so. These are one piece stamped decks with 3 equal-sized blades. With the Quietlines came the 38A, 44A, and 50A decks with the 38A being a stamped end deck, and the other two being just like the previous 44 and 50 decks. When the 82 series came along, the designations became 38C, 44C, and 50C, with the only change being the center pulley on the deck being switched from 1/2" to 5/8". The 44/50 and A decks are interchaneable, fit all WF tractors with a 1/2" belt, and will fit a NF with a number of mods. The C decks will fit the older WF's with the proper drive pulley. I could go on into what I know about CCC decks, but this ain't the place. Hope that all helps.