Colonel Richard Graham spent seven years as a pilot, and later, instructor on the aircraft, 1st Strategic Recon Squadron Commander, Director of Program Integration at the Pentagon, and finally, 9th Strategic Recon Wing Commander at Beale.
His words from "SR-71 Revealed", page 50.
The J-58 was the first dual cycle engine put into service. At subsonic and transonic speeds it was a standard , single spool turbojet engine, and it essentially transitioned to a ramjet engine around Mach 2.
One would hope the gentleman knew what he was talking about.
Ben Rich himself opined that the engine was an ancillary (my interpretation) in the production of thrust in the cruise, when he famously commented on the compressors as "pumps to keep the inlets alive".
Interestingly, in the cruise if the engine is deriched its contribution to thrust drops to 10% approx of the total, vice the normal 17%.
The F100/TF-30 etc have become partial ramjets
Not at all, they are engines designed and optimised for a completely different mission (fighter), and used in aircraft which are not designed for the sustained Mach 2+ flight necessary.