Leaving the 1850 on there would be the sensible choice. But nearly everything has been done to the engine with performance in mind, and I've still got the most basic 600 Holley on there that you can get. It just seems a little...boring, and doesn't look impressive (I know, that sounds pretty lame). This is my hobby and I work hard so like to spend a bit on the car where I can. The car is definitely stronger with the 700cfm double pumper, but has a big stumble off idle, which I'm working on fixing. The double pumper also looks way cooler with the dual inlets.