There are a lot of options available for a larger 4150 carb. The one I posted above is currently on my dragster, flows in the area of 1600 CFM, also available in a smaller venturi 1400 version. It will bolt on a 4150 manifold, but would require some machine work on the intake to clear the blades or a transition spacer. It is made by Get'm Garage, Mike Laws and Treavor Wiggins, Mike formerly part owner in BLP and Treavor was once VP of sales at Holley. They also have a new Titan metering block that I used on that carb. 461" SB2 in my dragster ran 4.712 @ 145 on Q16. They also make a newer version of the Little Bo and Mini Bo, 1000 and 1200 now. The 1200 is the largest carb that will bolt to a 4150 manifold with no modifications or adaptor spacers needed. All the above are dual pattern and will bolt to a Dominator flange as well, the 1000 and 1200 usually need a minimum 3/8" spacer to block around the outside of the manifold that is too big for the carbs.

BLP has a 4150 style 4 hole carb that can be bought in three main configurations, a 2" blade 1050, a 2.125 1250, and a 2.200 throttle blade. All three bolt onto a 4150 or Dominator flange, again on a 4150 manifold mods need to be made to clear the blades or a transition adaptor used. I've built all 3 sizes and run all but the 1250 down track with great results, It was run on the dyno and will be track tested soon but I expect similar results from it. They are also available in custom venturi sizes to go with each throttle blade size.

Braswell has a 4825 with a dual pattern, also available up to a 1.79 blade and I think a 1.65 venturi. I've reworked one for E85, and it worked very well. Braswell has the nicest castings out there.

As far as what to buy? Details on what you are putting it on, engine and car specs.