The middle picture has plugs I just pulled out this morning. You can see I'm still a touch rich at cruise with just a quick look. The porcelain should be a dull white.

The bottom picture are a couple of plugs I pulled and cut apart last summer. You can see tha shading on the upper part of the porcelain so I was still a touch rich, but if I went much leaner at a cruise I had a tip in issue. So you have to compromise sometimes.

In the bottom picture, you can see the fuel ring is better than .125 wide and has what I call a fade to it. IOW, as you move away from the shell, the fuel ring isn't well defined and fades into the middle of the porcelain.

The fuel ring is WOT. Depending on what you are doing, you can get as tight as a .060 wide ring with race fuel or alcohol. You need to be .100-.110 wide on pump gas. And no fade. The fuel ring should be sharp and clean with no fade.

This is an iron head, 11.01:1 pump gas 340. I have a Racer Brown solid flat tappet cam that is 281/281 255/255 .620/.620 on a 105 LSA in at 105. The intake manifold is a fully ported Holley Strip Dominator (I did the plenum back to square by welding it up and did a little welding in a couple of other places...wish I had done more welding) with a 1.437 Venturi BLP B4X carb.

I run Hooker 5303 headers with custom craft mufflers. I also run a Mallory Unilite with the curve locked out and the total at 36*. I also use a Mallory 685 digital ignition box. The plugs are Champion.

That's all I can think of right at the moment.


THANKS DAVE for posting the pictures for me. Hope this helps.