Well I'm just a basher, I always run 30%, I don't believe running with 30% nitro content has any effect on engine life. especially if it is the same oil content of a fuel with lesser nitro. The amount of oil would be the thing that effects the engines life the most, the nitro content would mainly just change the temps of the engine. So if your truck is running to hot for that fuel, you might want to think about switching over to a different one.