4 Barrel Red Throttle Body -For those of you wishing to switch from a carburetor intake to electronic fuel injection (EFI), Accufab has developed two high flow throttle bodies to meet your needs. The Accufab 4150 flows 1215 CFM and has four 1-3/4" brass throttle plates. The Accufab 4500 flows 2128 CFM and has four 2-1/4" brass throttle plates. Both styles have high quality progressive linkage and use late model GM electronics, included.