The bore may include a first radial inner surface at {HEAD ~ the first lobe portion} and a second radial inner surface at {TAIL ~ the second lobe portion} 
The bore may include a first radial inner surface at { HEAD ~ the first lobe portion } and a second radial inner surface at { TAIL ~ the second lobe portion }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL