They have to by lying, it was never "over rated" at 350hp, it was already de-tuned. Issue is they put this engine in fleet vehicles, fleet vehicles get driven by guys that dont care so they'd never unleash the full 430hp to those guys and apparently 350 was too much as well. If I had a motor home with the 7.3L I'd be looking for a tune to unlock as much as possible seeing as its not a fleet truck being beaten on by 47 different employees.