I have an aftermarket crossover pipe for sale (cheap)for stock headers if you think your crossover flange is warped. I'm a michigander also. Its an applied technologys ss 2 1/4" i believe.
I blew out my exhaust header gasket again (headers must be worped) and the car only ran with 13-14 lbs of boost and was only running 11.6x. Then in the start of the racing i get up to the line and start to boost up the car and i must not of pressed hard enough on the tbrake button and the car...
If you drive the car full throttle does the boost eventually come back up? I had a problem kinda like this before and it ended up being a bad torque converter. Mine would loose boost and slowly come back up. Took me a long time to finally figure it out.
Check all your vacuum lines and make sure they are hooked up right and that they are not cracked. Also check the boost solenoid to make sure its working right (you could wire the wastegate rod closed and see if boost goes up). Make sure no exhaust leaks before the turbo (headers or cross over...