There are many other factors that go into it including how your engine reacts. For instance, fuel mileage is extremely important when racing. We took a stock O.S. CV-R .12 against a TNT Mods modified O.S CV-R .12, both tuned properly, using the same fuel, in two identical trucks on the same track and the results were astounding. The stock engine got a very respectable 9½ minutes runtime. The modified engine finally ran out of fuel after 18¼ minutes! This may sound unbelievable to many of you, but this is absolutely a true story, and of course the modified engine performed much better.