In a preferred example, the engine has {TAIL ~ a spark plug access} well centrally located at the top of {HEAD ~ each cylinder} 
In a preferred example , the engine has { TAIL ~ a spark plug access } well centrally located at the top of { HEAD ~ each cylinder }
OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD