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OK, here is the long answer that boils down to them all having the same size pump. The catch is that (obviously) the gpm of the pump depends on how fast you spin it. My '49/'50 Red Tractor Book lists the Super A as 1040 cubic inches (about 4.5 gpm) at 2800 pump speed. It lists the C as 1225 ci (about 5.3 gpm) at 3300. Divide either of them out and you get about .37 ci per revolution. The pump gear has 16 teeth while the crank gear has 33, putting pump speed just over 2x the crankshaft. My '57 Book lists the Farmall 100 as 5.3 gpm at 3300 rpm. That is the same output and speed as was originally listed for the C. My '59 Book covers the 140 and 240 (in the same data column) to some confusion. They show a standard pump as 4.6 gpm at 2888 rpm and optional 9.3 gpm at 4125 rpm. I think the one listed as standard is the same size as the original, rated near the original slower speed. The optional pump is physically about 1.5x the other one, but the listed speed requires the 2000 rpm engine speed of a 240. As far as I know, the optinal pump was not used on the 140, at least not as a regular option. It was available on the 240, but probably only the 240, and was commonly installed if the tractor had much hydraulic equipment installed (maybe hitch plus remotes?). The general catalog spelled out combinations that required the bigger pump. The bigger pump was longer than the standard pump (longer gears provided the bigger capacity). The manifold that connected the pump to the Hydra-Touch system had a section of rubber hoses that allowed either pump to fit.
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