You ought to see if you can borrow a set of 30# and a MAF from someone to give it a try. Your heads, TB and LT headers breathe a ton more than what I'm allowed in T/S. More air needs more fuel. Just by the description of your plugs says that you might be running a little lean on fuel. I pegged 24# injectors out with regular GT-40 irons and an E cam. Every combination is different though so the name of the game is experimentation.
When checking plugs, the most important area is down inside the plug where the porcelein is in the body of the plug. You want to see some color down there right after a full pass. As you go through the traps, shut the car off an pull off onto the return area and immediately pull a plug. If you wait until you get back to the pits, you've ruined the read with rich & hot idle.
I only run my plugs (Autolite 103) down around 0.045-0.048 because of my compression. Any lower and I seem to loose some ET, anything higher than stock really hurts my ET. I'm also running a colder plug in the 103s because of the compression.
EGTs up around 1360F seem to be pretty common for the guys I run with. Its dependent on your combination, where you have the probe installed and a bunch of other factors so the main thing is to see where your car peaks in temperature and use it as a comparison from there as the conditions change.
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Jeff Chambers
Trophy Stock #3
11.86 Seconds / 113.8 MPH
Chambers Racing Team