This invention is easily implemented in {HEAD ~ existing engine structures} with {TAIL ~ only minimal extra machining operations} required 
This invention is easily implemented in { HEAD ~ existing engine structures } with { TAIL ~ only minimal extra machining operations } required
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH