I've seen it go both ways. I've seen many say a clean F-4 could no
way in hell break 2.2 clean despite the fact it reached 2.62 when it
was going for the speed record (yes I'm aware of the water injection
etc. etc.)

Early F-4B's were good for an easy 2.2 (skinny wing and lack of add-on
antennas) and I suspect with the right conditions and trimmed engines,
somewhat more. Best I saw was 2.05 out of a late J (S-config without the
slats) and it had the wing pylons attached. The Skyburner F-4 was the early
one with small nose and canopy ... certainly not representative of
production A/C.

On the other hand there was someone a while back that said
they were familiar with an individual who reached 2.83 in an F-111F
briefly even though it's generally listed as 2.5.

I've heard a number of claims for the F as well. It had higher thrust
engines and w/o pylons etc was VERY clean.

I know I remember
reading that it was limited to five minutes at a shot over 2.2 or so
because of heating. I guess the only way to know for sure would be to
get a clean aircraft up to it's optimum altitude, top of the tanks,
and put the pedal to the metal until you either stopped accelerating,
were about to exceed heating limits, or were out of gas.

It's usually gas and (these days) airspace. The F-8U3 never exceeded 2.39
because of canopy problems. Inlet heating is also a biggie.

LOL I wish
they'd do that for aircraft about to be retired anyway. I'd have
loved it if the Blackbird would have went out with new high marks for
speed and altitude.

I think they came pretty close with the last records. I asked Darryl
Greenameyer why the SR couldn't just do a nice smooth pull up from 80K for
the absolute altitude record and he said it wouldn't work.

R / John