sometimes a manufacturer could do a glider kit, basically a new truck on an older chassis and could use older engines. neat loophole found bc a glider chassis technically DOESN'T have an engine. i forget how that goes so i might be wrong but the idea is similar
I just looked it up, basically it is a new truck on a new chassis but with an older engine shoved in.
Now they are called the 589. I have seen a picture of a similar model in Oman. Mostly oilfield rigs.....One (or two?) Kenworth T800 for sale in Qatar, also likely an oilfield rig. Anyways, I hope the trucks of this mod can withstand oilfield use....
I'd say it would be 1987 because apart from it having a much different headlight assembly, it would come after the vanilla style hood (1972 - 1986) as part of the "newer" model lineup of conventional cab T-Series. Cheers!