67 Ford F250 stalling problem

I believe I have what must be a fuel related stalling problem. I moved here to Colorado last year and tried my best to high altitude tune my truck for a while it did fine ,however now it arbitrarily stalls it will just starts to "choke" I tried various adjustments to the choke but that does not help.
It will run rough and backfire and hestitate usually once it warms up. I am at a loss I was thinking maybe the power valve on the carb it has an edelbrock on it Im not too good with this altitude though so it may be in the tuning? Can anyone help?

Check for a vacuum leak.

Inspect your plugs for burn condition, ie., fat, lean, just right.