Was running a 650 hp and now i have a quick fuel 850 i am having the same issue with both carburaters.They work great at idle to average driving but at wot it is just like i shut it off when i let up it runs great.7lbs at idle but am afraid stock pump cant keep up.Should i switch to electric from mechanical?
What is everyone one else running?

 

I've got to bring this up, as a lot of perceived carb problems can actually be ignition issues.

What is your timing set to, and how is your vacuum advance hooked up?