4bbl running rich.

Here, read about these. Read ALL of it. There are some drop downs further down the page. I'm a BIG fan, one, because I have one of their 450s on my slant 6 and it runs GREAT and 2 they are a good bang for the buck. Read about all their adjustability. I'm not tryin to say run out and buy another carburetor. You may have constraints to work within. It's just a thought for now.
Quick Fuel SL-750-VS Slayer Series Carburetor 750CFM VS
I've been considering going with a Quickfuel VS carb myself over the 750 Ultra DP I currently have. I much prefer the vacuum secondary carbs. The carbs I've looked at are the 750 Slayer you mentioned as well as the 750 HR series. The only difference I see between them is the HR is a 4150 and the price tag shows it. Any thoughts about one being better than the other?