Possible Lean condition in L-jet motor - HELP, Fuel injection issues Options

[Cupomeat]

Ok, I am having the following problem on my 1.8l Ljet induction 914 motor.

First the basics;
1.9L (96mm big bore kit with KB pistons etc.)
8.4 to 1 CR
1.8 heads built out to 2.0l valve sizing, etc.
Stock fuel injection with adjustable FP regulator turned 15% higher than stock, currently(Pre-Lambda L-Jet, bummer)

Now, the symptoms;
Under normal acceleration, the car runs great and sounds fine, but under prolonged full throttle, the engine heat seems to go way up and pinging occurs. No pinging ever happens when I am rowing through the lower gears, but only seems to happen in 5th gear after prolonged Wide Open throttle (WOT).

So, my assumptions;
1. The car is going lean at prolonged WOT resulting in high head temps and pinging.
2. Ignition timing does not seem to play a role in this as I've played around with retarding the timing to decrease the pinging, but it never goes away at Prolonged WOT.

My plan;
1. Buy a WB Fuel/air ratio gauge and weld in the bung for the 02 sensor to support my theory

2. I have an inline fuel pressure gauge in the engine compartment, but can't watch it when I drive the car, especially in 5th gear at WOT (for very long, LOL)

3. Check to make sure the throttle switch is working to trigger WOT

4. If #3 is fine, is it possibly the fuel pump is running out of pressure?

5. I am also going to install a remote oil cooler to try to bring the heat down, but on a mild 1.9l, it seems excessive, especially as I probably have about 85 hp.

6.Probably install a cyl head temp gauge to try to pinpoint temps besides oil.

7In the end, if I have to pay for Dyno time to get to the bottom of this, I will but I'd rather not spend that yet.

Anything else people can think of? Any help/thoughts would be appreciated.

Eric