The DC-8's were not scrapped. All UPS has is the 70 series with CFM 56 engines. The reason why they don't fly to EMA anymore is because they have been used on domestic US duties while the 767 takes over on international routes.
UPS does not want a competitor to be able to take advantage of the investments put into the 8 though. UPS will continue to fly the DC-8 for quite a while and when an aircraft becomes unflyable then it will be used for spares.
Sorry I couldn't elaborate on the 727 more, DE727UPS could fill in the details, I need to get some rest