That could be too, but most manufacture's dyno the engine only with no accessories (power steering, A/C pump, fan, etc). You would be not beleive how much that can steal. Some times they put lower numbers for insurance reasons. For eg the 2004 Dodge SRT4, dodge says it makes 230 hp and 250 lb/ft but me and my buddy dynoed one that had 287 hp and 292 lb/ft. Dodge did this for one reason, so the insurance would be decient.