the ends of said heat exchanger extending axially of said {HEAD ~ exhaust pipe} for forming {TAIL ~ opposed wings} 
for forming
the ends of said heat exchanger extending axially of said { HEAD ~ exhaust pipe } for forming { TAIL ~ opposed wings }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL