Reading Andy's post again,1,700 will burn it down to the ground! 1,200 in a street car? Good luck with that as well. I've towed with my diesel at short times seeing 1,100 and 1,200 exhaust temps. Let me tell you, that fan clutch kicks in quick! That's making way too much heat for really, any cooling system to battle in a sustained environment. I would expect 5-600 at cruise.