for a little over 300 bucks seems like too good of a carb for the money. AND would this carb pull as strong as my 850 DP on a mildly built 440 up to 6 grand?
Thoughts and Thanks!

I would doubt that it would pull as good as your Holley. When I replaced my 750 DP with a Quick Fuel 680 I lost .010-.015 in the eighth mile. BUT, with that being said, I would not go back to my old Holley. I bracket race my car, and the 680 is much more consistent. I seldom have to change my dial in more than 3 numbers from afternoon racing to night time. Traction is less of an issue since the 680 is a vacuum secondary carb., and I'm now leaving on 2 barrels.

it is a barracuda with 440/auto 3:91.I have it tuned as far as I can go with my timming and fuel/jetting. the plugs look good but show a little to much timming as far as the FBO site considers. I don't like the idle on the 850 dp,everything else is good to great.I have a stumble but figure pump cam may fix that. I just can't seem to get the idle peged down.
highest vac reading is 13-14 with 6.5 pv.