I have a 97 DRW ,auto cab and chassis. Its always had a dump body on it. I recently bought it and am going through it to use as a work truck. I am new to the site and find myself here about everyday learning all I can. And thats alot. I plan on air filter,DP and straight pipe mods right away. Then go from there as the money allows. I have read about the differant injectors, size, splitshot. How do I determine what my engine has. 97 seems to be a year of evolution? Should I take my VIN# to a dealer and have them tell me? I am not sure of any mods before I got it so that might not work. I have maint sheets for the last seven years ( was a company owned truck) and they dont list any mods. It does show injector replacement. But they didnt change them all. Why I dont know. It has 139,000 mi. on it. Also what is the stock rear end. Dana 50,60 ? or corporate? Any help would be great.