Carburetion or EFI? It’s a dilemma that’s faced musclecar, streetrod and resto-mod car owners for years. The problem is that port-type EFI just doesn’t look right on most classic performance cars with its fuel rails and tangle of wiring. But when you consider the drivability and fuel efficiency of EFI, it just doesn’t make sense to use a carburetor anymore.

The solution is RetroTek Speed’s revolutionary billet throttle body that resembles a custom dual feed 4150-style carb. The BossEFI simply replaces the carburetor, (no new manifold or fuel rails required) providing a clean muscular appearance. It is identical in all critical dimensions to a 4150 and features four high-pressure port-style injectors placed strategically above the throttle plates, providing optimum fuel atomization and power output. In direct back-to-back comparisons to port EFI RetroTek’s BossEFI made equal or more power.

RetroTek’s billet throttle body is not the only unique part of its system. The Stage II Engine Management System has an “adaptive learning” feature that self-tunes as you drive – no laptop or tuning skills required. It takes its information from a wideband O2 sensor and control module. Also, no welding is necessary for the O2 sensor installation thanks to an innovative O2 sensor clamp that attaches to the exhaust. Another hurdle for EFI that no longer exists is the need for a fuel tank return line. The external RetroTek electric fuel pump is controlled by the ECU and provides exactly the right fuel quantity and pressure.

Two sizes of throttle bodies are available: the BossEFI 750 for up to 550hp, and the BossEFI 1200 for 550hp and larger engines. Dual BossEFI and supercharged and turbo BossEFIs are also available. Systems include all wiring, sensors and instructions. Installation takes about six hours.

For more information please contact RetroTek Speed at 469 Harrison St. Unit E, Corona, CA 92879. Phone: 951-737-2006 or visit www.retrotekspeed.com


Carburetion or EFI? It’s a dilemma that’s faced musclecar, streetrod and resto-mod car owners for years. The problem is that port-type EFI just doesn’t look right on most classic performance cars with its fuel rails and tangle of wiring. But when you consider the drivability and fuel efficiency of EFI, it just doesn’t make sense to use a carburetor anymore.

The solution is RetroTek Speed’s revolutionary billet throttle body that resembles a custom dual feed 4150-style carb. The BossEFI simply replaces the carburetor, (no new manifold or fuel rails required) providing a clean muscular appearance. It is identical in all critical dimensions to a 4150 and features four high-pressure port-style injectors placed strategically above the throttle plates, providing optimum fuel atomization and power output. In direct back-to-back comparisons to port EFI RetroTek’s BossEFI made equal or more power.

RetroTek’s billet throttle body is not the only unique part of its system. The Stage II Engine Management System has an “adaptive learning” feature that self-tunes as you drive – no laptop or tuning skills required. It takes its information from a wideband O2 sensor and control module. Also, no welding is necessary for the O2 sensor installation thanks to an innovative O2 sensor clamp that attaches to the exhaust. Another hurdle for EFI that no longer exists is the need for a fuel tank return line. The external RetroTek electric fuel pump is controlled by the ECU and provides exactly the right fuel quantity and pressure.

Two sizes of throttle bodies are available: the BossEFI 750 for up to 550hp, and the BossEFI 1200 for 550hp and larger engines. Dual BossEFI and supercharged and turbo BossEFIs are also available. Systems include all wiring, sensors and instructions. Installation takes about six hours.

For more information please contact RetroTek Speed at 469 Harrison St. Unit E, Corona, CA 92879. Phone: 951-737-2006 or visit www.retrotekspeed.com