That was when the car was still stock, I only drove it about 5 miles with the h/c package and then filled the tank with 93. There was no spark knock after that, this is a new problem that arose after the thermostat stuck.

 

How exactly did you determine the tstat was stuck closed?
Put it in some boiling water and it never openned? or just guessed?

If this overheating & coolant leaking happened so soon after a head install I'd have to say the gasket just didn't seal.
New headbolts were used right?

 

New head gaskets and bolts were used, torqued to spec. The thermostat didn't open @ 220 F in boiling water. I gutted the thermostat because no one had it in stock. The car was fine, didn't overheat or loose any coolant till yesterday.

 

Oh

+1 advantages for not running a thermostat.
It doesn't happen often but this goes to show it can be bad when it does.
Yeah obviously the mating surface/s have warped now from the overheat, so they need to be straightened.
You probably did nothing wrong on the assemble... it's just bad luck about the tstat.

 

Thats what I was thinkin