What an incredible photo of the GE
747-121 with the GE
engine under the left wing! The difference in size is amazing. I believe most of the early 747's had engines with thrust ratings of 45,000 to 46,000 pounds, or thereabouts. Someone can correct me on this if I am wrong. However, if accurate,
then a pair of the 90,000 pound thrust GE
engines used on the 777 should easily be able to fly one of the older 747-100's, providing that the 747 could be adapted to use them. A pair of GE
90's would not look out of place under the wing of a 747-100, and might actually look pretty sharp!