I installed an exhaust brake on my Cummings Dodge 4x4 (1991). Can't remember the brand. It was one of the major ones that I saw in a four wheeling mag. It was easy to put on, and I had to change the exhaust valve springs to 90 lb. springs. They came with the kit and were easy to install. You must follow directions carefully and be very comfortable with the mechanics of it or else get a professional to do it. It worked as advertised and provided about 80% of the engine horsepower equivalent on braking. On gravel roads it would skid the rear wheels when in lower gears, it had a lot of dynamic braking torque. On pavement, make sure that everything on the seat and dash is tied down or it will end up in the windshield. The best part was the sound. It was just like a big rig. I got a kick out of driving by my friends house at 40 mph in 2nd gear and letting off the accelerator and turning on the exh. brake. It really scares women and small children. I think they are only avail. for diesels though. Hope this helps.