Cab, the op is in oregon but yes, Reno's almost 4800 ft elevation
& our 91 pump gas sure isn't the best stuff. Hopefully, we'll dyno my 440 tomorrow & see what numbers it makes with a good tune & carb we just rebuilt. I don't know the cam specs, but it is a purple shaft hyd & didn't pull a lot of vacuum the first go round, so it may be bleeding off some compression as it didn't show any signs of detonation. Of course, everything is new in the motor, so there's no carbon build up in the heads yet. Anyway, maybe we'll measure the cam & do a cyl pressure test. I was pretty amazed that an iron (906) head 440 made that kind of power, but that 512 6 pak motor you built made some impressive power. I would think the op's 440 should be close to what mine made since he's at lower elevation.
Also, I do remember a few yrs back, a 426 iron head Hemi I had was close to 10:1, had a big cam & didn't ping in Reno, but sure did at sea level.