I would be the last one to second guess a cam company's recommendations, it looks like they were taking into consideration the altitude that you are running in, But for me in the conditions that we run in (close to sea level) it's a lot of cam. Example this past weekend Memphis corrected altitude 1500 ft. course we burn 1 gal of fuel and 1/2 gal of water with all the humidity that we have.
One thing you didn't say are the ProComp heads fully CNC ported. If they are they are supposed to flow 374 CFM, if they are not CNC ported you'll be lucky if they flow 320 CFM. I sell the Pro Comp heads but not for racing, due to all the complaints that people who have never ran them lay on them, and i would definately not run their valves (which you're not)
The heads on the 468" that i built are Brodix 2 Extra's and they are fully ported, but i doubt if they flow more than 340CFM, we're hurting the performance some what because we're running street headers 1 7/8" with a 3" collector so we can bolt on mufflers, we're also running a Edelbrock 454R intake with a 1050 Holly.
The other thing is that you said you had a 4800 stall converter, the cam they recommended says 4500/7500 operating RPM, it's not easy to turn 7500 RPM at 7700 ft elevation, with a 2900 lb car less driver i think i would look for a little lower power curve, but you'll never know unless you try their recommendation.
JMO
Zip.