Plane Speaker:
Almost right. While both engines put out a maximum of 7000lb of thrust, the 507 is rated to a higher temp than the 502 (because of the difference you describe), hence the 507 is much better in hot/high conditions, and hence the ability of the NJS -300s to thrash those gutless old Eenie Weeny bombs (onya EWL). Bit of a shame they didn't actually compete head to head: AN wimped out and put them all in NZ (nice and chully). They didn't help their own cause by absolutely thrashing them up and down the QLD coast in the early 90s trying to keep the sched: I'm sure that didn't do them (the donks) any good.