I have run a few different carbs over the years but I gotta say I do like how nice the Holley 750 to 850 Double pumper works. I run the Holley 850 DP street version that had a choke which I removed but of all the carbs I have used I really like it. I only did a few minor mods to it because it just works so nice. Works fine at the track and has great driveability on the street. We run a Holley 750 DP on my sons 400 Dart and he loves it. We have had 3 different carbs on it and he always goes back to the 750 DP because it just works so good on his combo. I am sure I can go faster with a Dominator or one of the race carbs but for all around performance and driveability I love the 850 DP on my 63. Ron