Well, it's about that time again. This V6'er hasn't asked a stupid question in a while so I getting a little restless. If everyone could be so kind as to read the whole post first, then you can all take turns beating the sh*t out of me. I've been reading up a little on increasing compression on our 4.0 engines, because I read on the interwebs that that's a way you can increase performance. "Keep Reading" Now, in understand that the traditional method of doing this is through the use of a turbo or super charger to ram more air into the cylinder. I also came across something, of course I can no longer find it, that talked about decreasing the compressible volume as a way on increasing compression. I found that option interesting, as it's most likely to blow up in my face, and I can really only think of one cost effective way to do it. "Almost There" The pistons and valves, you can't really change those, unless you change them, and that wouldn't be cost effective. But what about the spark plugs? Is it possible to use a larger spark plug to decrease the compressible volume? When I say larger, I mean the part of the plug that gets screwed into the engine. It's an idea that's been rattling around in my head, so I wanted to put it out there and see if anyone had any thoughs on it. Ok, if you've made it this far, you are now free to do your worst.