This tip is from an interview we conducted with Steve Hendren of Hendren Racing Engines: "I see guys who don't run any type of cold air box. If you show me a guy who has his air cleaner half under the hood and half sticking out above the hood with no cold air box, I'll show you a guy who is throwing away 10-15 FREE horsepower at the rear tires. I can prove this on the chassis dyno all day long. Cold air is critical on these limited horsepower engines! Crate engines don't have 10-15 hp to simply throw away because their engine is breathing and trying to compress 200 + degree inlet temperatures. With a little bit of aluminum work, or by purchasing a pre-made cold air box, you can isolate the air cleaner from under-hood temps, and gain back the free power you're throwing away. People always hope that I can find them 10-15 hp in their engine, when a lot of times they can spend a little time and very few dollars to free up 10-15hp themselves."