Which type of carburetor?

I'd open up the ports to 360 size, suppose to give 20hp. They have to use them on late models up here. If you don't open them to 360 size they find the stock 2 bbl intake faster And I imagine the stock 4 bbl is better than the stock 2 bbl intake.
(They have to run a 500 cfm Holley 2bbl)