I have a 190 in mine and my experience with Class 8 rigs tells me they will have a bit more power and get a little bit better fuel mileage running at 190 or a little more. I don't recall what the computer showed on the trucks that had them but it seems like they ran about 200*. Been a few years since I have been in one with a 'puter though. If it is important enough to you my bro's rig has one in it but I am not sure it is still working since it has over 750,000 miles and 10 years now. :lol3::CRY::thumbsup