<<dunno why NW is so hung up on PW engines...
>>
Actually NW has GE/CFM 56's on the A319/A320 fleet and GE/CFMs on the DC10-30 fleet having retired the PW DC10-40s.
Given that PW was only original choice for 727 and DC9 which they inherited and the PW on the 707/720/320x not surprising PW influence.