I'm working on my buddies duramax and it has been sitting for a while and now I'm trying to get it going. ive got it turning over fine and trying to get it primed up. its blowing a lot, ALOT of white smoke and acting like its wanting catch an fire up but never does.. the man says it might have a blown head gasket but he isn't sure and I'm not sure the full background on the truck to be able to give a detailed explanation on exactly what happened when it quit. just wondering what to do...ive been priming the hell out of this thing and still wont start. any ideas? ohh btw its a bone stock(to my knowledge and what I can see) 2005 chevy duramax 2500hd.