Pushrods 30 may be engaged with {HEAD ~ the camshaft} 26 to actuate {TAIL ~ the rocker arms} 32 and selectively open the intake and exhaust valves 18, 20 
to actuate
Pushrods 30 may be engaged with { HEAD ~ the camshaft } 26 to actuate { TAIL ~ the rocker arms } 32 and selectively open the intake and exhaust valves 18 , 20
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH