said concavity at said trailing end of said concavity having {HEAD ~ a depth} sufficient to accommodate {TAIL ~ said impeller} such that a central hub of said impeller is positioned at an elevation substantially equal to an elevation of said output shaft of said engine 
sufficient to accommodate
said concavity at said trailing end of said concavity having { HEAD ~ a depth } sufficient to accommodate { TAIL ~ said impeller } such that a central hub of said impeller is positioned at an elevation substantially equal to an elevation of said output shaft of said engine
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH