{HEAD ~ an outer cylinder} depending from the insulation cap and at least partially surrounding the inner cylinder to define an annular exhaust gap for exhaust gas from {TAIL ~ the exhaust plenum} 
{ HEAD ~ an outer cylinder } depending from the insulation cap and at least partially surrounding the inner cylinder to define an annular exhaust gap for exhaust gas from { TAIL ~ the exhaust plenum }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL