race truck help

[powerstroke_23]

Im in a 4 cylinder truck class at a local dirt track and just bought a new truck. I ran it for the first time thw other night and i cant rev over 6 grand. Its got the 8 plug motor in it and im tryin to figure out how to do away with the the rev limiter until i get my carberuated motor buult. The motor in it is mildly built so itll take more than 6 grand. Any help would be greatly appreciated. Thanks