sea level to 7000 ft

[Javy]

I recently drove my 427 powered CST to Big Bear.CA (7000 ft)from Los Angeles,Ca.After 4000 feet it really started running crappy and even my 4 wheel power disc brakes suffered.I understand with less oxygen it's going to
run rich but I never have experienced this condition before.I'm running a above average cam so I expect not to have the best vacuum available for
my brakes.Due to this high elevation I'm here to tell you guys it makes a big
difference.
KUDOS to crew chiefs that tune Hot Rods at Denver NHRA events!
I welcome any comments or recommendations.
Thanks,
Javy