The folks at
AED Performance | Racing Carburetors | Holley Carburetors are at the top of their game.
I tried Pro Systems. Patrick was a pleasure to deal with, but after 3 tries he was unable to build me a carb for my Roush 427R that met my requirements. I am very lucky to live about 15 minutes from AED. I drove over to their shop and spent about an hour on their chassis dyno while they custom built a carb for me on my car. The result was flawless. Instant off idle response. Nice nearly flat A/F ratio. Great HP and torque numbers. I couldn't be happier.