I'm gettin' about one degree of KR for every pound of boost, all the way up to 15* at WOT. This was last night at 54 degrees ambient temperature. The biggest difference between now and WCBF is a swap from autolite 104'* to 103'*, and half a tank of 100LL. Would either of these be contributing to it? Or is there another reason?

If the plugs are the only significant change you made, I would strongly suggest you try some TR6 plugs - 2 ranges cooler.
I have absolutely no KR now running 94 octane with either 3.1 or 3.2" pulley.

What size pulley are you running 3.0"?......but that should not explain the KR at low boost. :?

LL? LOW lead? Not unleaded? Be wary of that. It'll kill a cat and an O2 in short order. Which could be part of your problem.

In addition, don't forget it takes time for the timing to learn an octane change, and winter gas mixes suck for performance.

That'* right. The leaded race fuel I ran at Woodburn killed my O2 sensor. Shadd doesn't have a Cat.

What did you gap the plugs to?

Plugs gapped to .047 with 103'*. I do have a cat, and I'm kinda expecting to replace it and my O2 sensor once I get this gas out of the system. Yes it'* 100 low lead. I've been back up to a 3.4, but it'* gettin nasty KR. I'm afraid to drive it, I don't want to pop a piston, and I really have no clue why KR'* so bad.... :(

3.4" and KR with your mods is strange

Try opening up the gap on the plugs .005" and see if it makes any difference.

What engine coolant temps are you seeing :?:

False knock maybe :?: Is something vibrating on the engine....like exhaust header and trani dipstick :?:

Coolant temps are solid at 180, I haven't noticed anything obvious that would indicate falst knock, I'm gonna get some new plugs and see what happens, these may be staying too hot and pre-detonating. If it'* not the plugs, I have no idea what the problem would be.

Cooler temps make denser air which means more boost. This means hotter cylinder temps. If your 02 sensor is bad or failing your a/f ratio could be way lean causing detonation. Your fueling system may have a problem causing lack of fuel to the cylinders. I would scan the car and find out whats going on....

That was my thought too. That leaded gas probably wiped the O2 out.

Have you tried just unplugging the O2? With the sensor unplugged it should go into rich limp mode.