I have been slowing my car down from a high ten second car to an 11.50 car for many years now. Last year we tried 11.50 index racing and Won a Track Championship. I don`t use weight ( I`ve had one hernia surgery and don`t want another) but I use a Moroso throttle stop , mine is modified a little but it bolts to the corner carb bolt and can be set to restrict the throttle from opening all the way ,on my car the secondaries are barely opening and one turn is about 6 hundredths. A word of advice if you use it don`t just use the one bolt to hold it as it will turn slightly on the stud/bolt. I purchased the Jegs throttle cable/return spring bracket which also mounts to the carb bolts/studs and simply drilled another hole and added another bolt so it can`t move. I have considered a plate system but my results with my current set-up have been great.