I'm not superior at diagnosing problems, but I know the basics. My '97 Sierra took a crap today, unless my wishful thinking is true. Driving down the highway, the oil pressure dropped to 0 psi, engine shutdown and I pulled over. I opened the hood and it smelled of oil pretty bad. There was some oil burning off of the valve cover. The engine will not turn over and seems to be seized. My guess is either the oil pump failed or a head gasket blew possibly. If anyone has any insight it would be greatly appreciated, even if the news is I need a new engine. Thanks in advance.