I'm running regular ACDelco plugs. It is harder to access them though. I have to crawl under the truck to reach some of them. As for the bolts, well like I said, they need to be header bolts. the heads on header bolts are smaller than on regular bolts. I also torqued my header bolts. There was only one that I had to use a boxed end wrench on. I bent the little 7/16 wrench I used for that bolt. I had a cheater on it about the second length as my torque wrench. At first, I did fight some leaks, but torturing the bolts was the trick. Well that and some good Felpro header gaskets