bigredexpress99

iTrader: (15)

Yeah the partnumber stayed the same but the whole camshaft profile changed.

60Chevy

FYI, I work in the auto industry in Detroit. If you change something as small as the surface finish of the bearing journal on the camshaft, you have to re-assign a new part number to the camshaft both engineering and service part numbers. Then you have to show to the EPA, usually through paperwork and test results, that the camshaft does not impact emissions not only for the new model year, but if the camshaft is meant to back date to previous models, you have to prove emissions compatibility there too. Changing cam timing points is bigger can of worms. I don't work for GM but their system is the same as Ford and Chrysler. Between the US EPA, California ARB, and the big 3's own engineering procedures and record keeping, I am always amazed they are able to actually design, release, and manufacturer a vehicle.