You will never get an 8.5 power valve to close at that altitude- put an 4.5 PV in and go down to 50 jets-------your problem is running rich with low/no vacume that the carbs circuits will work--------Make it LEANNNNNNNNNNNNNNNN and then come back up -----
In artillery-----over, under, adjust----------your over!!!!!!!!!! now get under!!!!!!!!!!!


I've never heard of a Brawler carb-------does it have mechanical seconaries and maybe even 2 power valves???????????