This E-tube has a slightly larger main bore and less air bleed holes providing a better fuel signal at the jet. Improves performance across the RPM range, but especially on bottom end and mid range. You will want a main jet between .035" and .037" depending on how much you can bore out the carb venturi and which cam you use. This tube is legal in both Superbox and BP. It is not permitted in Box Stock.
This custom bored .650 carb is designed for the Stock Appearing or Outlaw class and offers a special built ultra thin throttle shaft and knife edge butterfly that greatly increases air flow. Reworked air circuits and a unique E-Tube help regulate the fuel signal to give you that "little extra" power and RPM you have been looking for. Available in Gasoline and Methanol versions. Both will come jetted and ready to race and require no extra work to the insulator or air filter adapter. Choke top in place to appear stock. . Alky carb is capable of pushing 20+ Horsepower on properly built engine.