If the heads flow more cfm and boost drops, then ACT's will not be as high. Less friction, less heat, you're right.
These AED cars hold 3/4 of a gallon of fluid in the hoses, water tank, pump, heat exchanger and I/C core. If you followed AED's directions and filled the system with a 50/50 mix (which covers people in Canada and in Florida), then you essentially have 1/3 of a gallon of water cooling of the blower discharge temps. The anti-freeze does nothing to remove heat. You could just use straight DISTILLED
water and no anti-freeze, but if the ambient temp drops low enough, you'll freeze everything. This means you'll get heat soaked fast. The initial WOT blast may be fine, but repeated WOT runs will bring higher and higher ACT's each time. The reason is, the coolant mix in the I/C system can't remove the heat fast enough. For 6-psi of boost, I think you'll get by ok, but the 2.5" pulley makes a ton more heat. The HEaton M90S likes to make more heat than useful cfm.
The solution is to add more capacity to the system. I added a 4-gallon fuel cell to the trunk, added a second heat exchanger,and ran dual Bosch pumps. The coolant is 80/20 distilled water and Dexcool anti-freeze with a bottle of Redline Water Wetter. I filled 5 gallons in this system and it seems to be working nicely. Blown96bird, followed my suggestion and did the same basic set-up as I have. He was pleased with the overall ACT's at WOT.
In order to lower the ACT's at WOT with the smaller pulley, you will need a larger intercooler core. No way around this. The AED supplied Spearco core is not up for the task of 10 psi of boost and you can see ACT's in the 170-180 range on a hot day. A double core intercooler would drop those ACT's substaintially. With the 1" spacer it would be possible to do such a mod (see I was thinking when I selected 1"). Problem is, AED doesn't have enough demand to warrant the production of the proposed I/C double core intercooler.
Mike, you need to get a 110.5" belt or so. Dan Newman stocks JK6-1106 belts that are 110.6" in length. Like I said before, the stock belt is 111.8" and won't be up to the task of the 2.5" pulley. If your boost and fuel pressure drop off at WOT, then come back up...your belt is slipping. I don't have the p.n. for the gatorback handy.
Dayco also has a 110.5" belt as well.
Your numbers are good, but a tad high. I saw 182-185 when I did my test. I assume you took all the spark plugs out when you did the test.
Sooty plugs are better than white/blusish! Red tint on the porcelain means you have seen some kind of additive either in an octane booster or in the gasoline. Nothing to worry about.
My original set-up when I made 325 RWHP/380 RWTQ (SAE) was with 30 lb./hr. injectors. The A/F ratio was 11.7:1- 11.9:1 and the car was seeing 45 lb./min of airflow. So that's 28.85 lb./hr. of fuel at each 30 lb./hr. fuel injector or 96% duty cycle at WOT. Way to high for my tastes. So I swapped in 36 lb./hr. injectors and had SCT retune the car. It didn't make as much power since the ambient temps at climbed to 80 F., but the duty cycle had dropped to much safer, 78% at WOT.