Mine ran lean lean lean and burnt the valve.

The problem with mine was that the line coming off of the intake manifold to the ISV had popped out. Causing the mixture to screw up royally.

And which made it worse, the knock sensor wasnt connected either, causing the knock protection to fail.

 

Actually if the ISV line popped off you will run rich under boost – and that will crank up the EGT and cause the burnt valve. Rich mixtures burn slower and create a situation where the mixture is still burning when the exhaust valve opens – bad news for the valve!
A big vacuum leak is kind of counter intuitive – it runs lean under vacuum and rich under boost. The vacuum lean is no or low load so there is not much danger.

 

Hmmm interesting. But youre saying that the valve was most likely burnt by this? A little additional info, the car had a K26/6 with stock chips on 15 psi *i know I was dumb*.

 

i have 951 heads availible and in good shape. let me know if you need one

 

Yep, the combinition over overly rich and the high intake temps casued by running the K26/6 that hard will give you very high EGTs.
Detonation tends to do a lot more physical damage - usually the spark plug electrodes are the first to go.
Once you take it apart you will find the exhaust valve has a pie shaped wedge cut out of it - it looks like it was done with a torch!

 

No telling what that little pie shaped piece does on its way out of the engine? Or it could just stay put and chew up the cylinder.

 

How can you run 15psi boost with "stock" chips?
With stock chips you will hit overboost when running at 15psi (not a 15psi quick spike).

Another variable to examine.

 

If you remove the KLR vacuum line and run it to a AM boost gauge, wont that allow you to run higher than "overboost point" boost levels?

 

No, the Boost line to the KLR has nothing to do with overboost!

The KLR has nothing to do with detecting overboost. The DME detects overboost (actually overload) then tells the KLR to do its thing.
In reality, (except with the V-FLEX software) the DME never did read actual boost as in psi/bar. It calculated load, and based on load it determined the status.