The UPS 727's are powered by RR Tays, that have approximately the same amount of thrust as a JT8D-17. Also UPS will be flying them for many years to come as they are stage 3 compliant, and I'm told possibly stage 4 if it occurs due to the Tays. All 52 -100 models are Tay modified, but they also fly 8 -200's that are hushkitted (JT8D)