Siren,
If Holleys are so good, why is every man & his dog making 'better ones'......
They are a crude design & the power valve arrangement approaches joke status....
Really go to the track some time and see what people who race seriously are running.. Holley like carbs. have drastically improved over the years,my last 2 carbs. were Quickfuels 850 "BEST" carb I ever used,then again I know how to tune which I did when needed for weather conditions..