Glenn is right on the money. But I might add,it would probably be a good idea to change the cam and lifters out because if I remember correctly thats about the years that G.M. was having trouble with cams going flat. I would change it out with a roller set up because the oil we have today will not work with flat tappet cams. I don't have a cam recomendation, but I would not get very radical with it.