Meanwhile, the carbs would be baselined against our dialed-in 750. Here's the new 870 Street Avenger, which we used in our first test. The Street Avenger offers a lifetime warranty on parts and a one-year warranty on labor. Equipped with an electric choke for street use, it also has a unique quick-change secondary spring feature and comes complete with three different springs, air cleaner stud, fuel line kit, gaskets, and instructions. In our initial tests, simply swapping to the lighter spring was enough to improve the e.t. by a few hundredths. In our opinion, this carb would be ideal on a big-block door car with highway gearing.