Spark plug misfire?? you must read this!
 

So my motor is running and having issues, on investigation I remembered once I figured out I had a plug issue that when I pulled my AFR 227heads to repair them and install the cometic gaskets I noticed that on some of the cylinders right at the plug there were small lines that looked like arc lines across towards the valve. not all cylinders showed this just a select few. when I screwed in the plugs the ones showing the marks were because the threaded hole in the head sets it so the arc and center of the plug aim toward the head and arc across it when firing twice with a MSD. being that everone I talk to runs NGK TR6 plugs figured it wasnt a issue. but now that Im having issues Im looking back at this think having platinum or E3 plugs would solve this? Any ideas or anyone ever dealt with this????

Running Platinum is not a good idea as they are not recc by AFR and with those heads will probably foul out quickly (since you are probably running a stout cam). Also, I would steer clear of the E3's as their quality is for shit. A buddy of mine and I put a set in his truck last year and half of them were cracked out of the box and 2 failed in the motor after 500 miles.

You are using the gasketed type plugs as AFR reccs - right?

If your idle is rich then you will foul plugs. Once an NGK plug is fouled it is garbage. I use Autolite plugs after fouling a set of NGK's in a couple days.

Yes but if my plugs are fouling out against the inside of the head then it'll always have an issue. maybe Im overanylizing but the arcing across the head cant be efficient or correct. Anyone ever shim a plug???

NGK TR6's ???
your saying they recommend the plugs with the metal rings around them?

Nobody at AFR said a word and I even mentioned the arcing issue to them?
Hmmm always trying to sell new and not helpin with the stuff already out there. Typical.
what plugs you running with yours?
my heads are older design 227's for LT4. there arent all cosmetic on the outside like the new ones but healthy on the inside.LOL

If your afrs have a flat surface where the plugs go they take a gasket plug will look like 90deg into plug hole no taper. The other type tapered plugs will have. A taper like a an fitting on the head. These are not interchangable. Taper seals on a taper head and same with the flat gasket type. Check your instructions that came with the afrs or hit their site.

Once u figure that out u can get moroso indexing washers.

yeah thats it I was wondering about indexing them, they are the tapered hole wthout washers though apparently AFR made the older comp heads this way which is whhat I have. do they make indexing washers for tapered plug?

Ah found em moroso indexing washers for tapered plugs cool man you just made my day or night those will work perfectly. just have to take my time on each plug and index them all the correct way. guessing you only index the problem ones.

The spark will take the path of least resistance. If the plug is fouled it may arc to ground which is what you are seeing. Are you sure you have plugs with the correct reach for the head you're using? If the plug isn't sticking into the chamber far enough that could be your problem.

Too much anti seize compound in the plug threads can cause your issue as well, if you didn't use any indexing is your best option.