I have a 4-hole throttlebody that has been machined to provide the maximum amount of flow through a 4150 flange manifold. It is now a 2 blade throttlebody that will flow over 1500 cfm.
A custom idle air control housing was machined for idle control. It utilizes an LS1 IAC motor to bypass the most amount of air possible. This allows large aggressive cams to idle under 900 rpm! The center area has been machined so the center stud is no longer present. Instead a separate bracket is included to hold down any standard carbeurator air filter assembly.
This unit will outflow anything on the market including the Wilson Manifold 472175 throttlebody which sells for over 700 dollars bare. I am selling this throttle body for $600 shipped including the following:
Throttle position sensor,
Billet IAC housing,
LS1 IAC motor,
Filter bracket,
Progressive throttle linkage with return springs
Pictures available at http://s564.photobucket.com/albums/ss89/pics595/ThrottleBody/?albumview=slideshow