Bought this pump to replace a noisy original pump in my Silverado 1500 2004 2wd VIN "T". The pump looked exactly like the one I removed except the new block was tight and looked almost too good to fit in a dirty engine bay. Installation is very easy, except you'll have to run to your local auto parts store to rent a pulley puller tool. Remove the pulley before removing the pump. The end result is quiet, trouble-free operation. Couldn't be happier. AC/Delco is usually the best choice for any GM platform and this part is no exception.