{HEAD ~ A cam plane} is defined perpendicular to the longitudinal axis and disposed between the open ends of the cylinders and {TAIL ~ a second end} of the engine housing 
is disposed between
{ HEAD ~ A cam plane } is defined perpendicular to the longitudinal axis and disposed between the open ends of the cylinders and { TAIL ~ a second end } of the engine housing
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH REL REL OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH