AM General still builds the High Mobility Multipurpose Wheeled Vehicle (otherwise known as the "Humvee") for the military, both ours as well as our allies still use them.
Also, the Optimizer is available in the aftermarket. It is a popular upgrade for folks who love their older GM diesel C/K trucks as well as some P-vans (later known as Workhorse, until GM sold that division and was eventually taken over by Navistar).
Because most all the old 6.5L cores are no good for rebuilding, and the Optimizer is an easy drop in replacement for all of the older engines, and can be configured for both turbo and non-turbo arrangements. I have a customer with a '91 2500 Suburban that has one. It is not a 7.3L PS Excursion, but it gets the job done and has covered over 200k miles since install and the engine has needed nothing but oil and filter changes and a drive belt. That's it. They increased the oil capacity from 7 quarts to 10.5, it has a water pump that flows 50% more, and a much more robust block and cylinder head casting. He tows his race car and trailer all over the place with it. The 4L80E transmission has been rebuilt/replaced several times. The last time it got some fancy controller that is supposed to make it last longer, I think that has helped it a lot. There is a kit to convert these over to an Allison transmission but it involves a body lift for clearance on the GMT800 chassis.
