They run just okay out of the box. They build them to be a "no hassle" kind of carb. It's like Windows. It work good enough for most but you can't do much with them. They don't get the best mileage and don't make the best power either. Holley, QFT, Proform, AED, etc... are like Linux. They take some tinkering to get them just right but when you get them right, they'll outperform anything else you put up against them.I actually really like edelbrock carbs. Anyways its looking really good. Interesting spark setup you have going on. Wouldnt just a better distributor help out better?
If it was me, that 351W would have a Holley 850 DP with annular boosters, especially with the dual plane manifold.