I have a 670cfm Truck Avenger on my '70 W100 and it is a nice carb. A bit lean out of the box, but still a good working carb.

On my mild 440 I used a 750cfm Quick Fuel Slayer which is a vacuum secondary carb with all of the tricks (replaceable air bleeds, externally adjustable vac. dashpot, glass bowl sights, etc.) and it has worked great all winter long.

The QF Slayer is $300 compared to the $360-400 for the Holley that has less features.