I am going to change the head gasket on my 2004 GTP comp G and want to get the heads done before I tear into it. I am going to go to my local pick-n-pull and get some heads but wanted to make sure that all 3800 heads are the same. Can I just pull any head from a Pontiac or Buick that has a 3800 engine and have them done? Does the car have to be supercharged? Are there certain years that are beter then others? Thanks in advance for your reply.