Probably there was a more "sketched" assembly drawing as with Stuart current kits.
About the valves, it has only a delivery valve (12) in the head and the intake is through a port between the cylinders, uncovered at the bottom of the stroke
Li trovi sulla rivista "Home Shop Machinist" 1993 vol.12 N.3-4-5-6 (Devrai cercarla usata perché non so se ci siano state ristampe)
PS. Aggiungi la traduzione in inglese anche se da google ;)