451 overheating, even when moving

I used the 18" derale recommended in #30, no shroud.

All fans have been removed from the engine for now as I figure out what's next, but I'm leaning towards taking it to a father/son mechanics shop who go drag racing on the weekends. The father has been hurtling Mopars down the strip since the 60s and is semi retired, but I think he'll welcome the opportunity to sort this.

What the heck happened when it was flushed?!?!