Salute!
Yep, it was Shul ( former student of mine and fellow Green Demon of the 356th TFS at The Beach).
PLZ refer to the actual Dash-one and other good stuff here:
https://www.sr-71.org/blackbird/Many "less than accurate facts" about the engine design and such are out there. The dash-One explicity describes the engines and they were not "turbo ramjets". Ben Rich nailed the speed limits being compressor inlet temp ( like the F-104) and inlet shockwave management ( they are highly related), duhhhh My friends that flew the thing, including Shul, may tell you their "indicated mach", but it would not be more than a few decimal points above the tech order numbers.
For now and until we see the "Aurora" numbers, I'll stick with the Blackbird speed and altitude numbers.
Gums sends...