As far as I remember all 40 chain frames were originally sprocket tensioners
Edit, disregard that as I'm an idiot, the Turd is 40 chain with plastic style adjusters. The 40 and 50 chain machines were out together with the HP determined ing chain size.
, all plastic ones should be the same width.
Sprockets were 22 tooth on the 50, though I don't remember if the triple sprockets had different center counts.