Mostly metric in body, chassis, and external engine accessories. Many engine fasteners remained imperial well beyond that for "archive" engine designs, like the Buick V-6 and Chevrolet SBCs well into the 2000's. There are a lot of 7/16-14 bolts in a Vortec engine with six or eight cylinders up through 2013. That makes it handy to have lots of a wide variety of tools.