I'm using one of these with a q-jet
http://www.summitracing.com/parts/CRT-M6900/
Works good with a .130 needle seat and 5/16" float level. Puts out a bit too much pressure for a larger seat. I never had a gauge on it, but I know I had issues when I tried to go larger with the needle seat. With a stock fuel filter in the Q-jet bowl and 3/8" line, this set-up is good enough for 12.9x @ 108 mph in my Chevy II (355 ci).