DL_Mech From United States of America, joined Feb 2000, 1769 posts, RR: 10 Reply 1, posted (13 years 1 month 3 days 2 hours ago) and read 615 times:
On the B747-400/767, look for the precooler air outlet on the silver (aft) part of the cowling. It is square, darker gray in color and has three fins on it. If it is a Pratt, it is on the left side. Remember "P" Pratt=Pilots side. GE outlets are on the right side.