I had actually, finally sold the Grand Prix!!! But it came back
The guy messaged me a couple of days after he collected it to say it had overheated and blew all of the water out. I went to check it and looks like it's head gasket! Nothing he could have done wrong so we reversed the sale. Just one of those things I guess. It hadn't had any overheating issues before, but there was some brown mush in the radiator which looked like it had been there a while. I hadn't opened the rad for ages, I had no need to. Apparently the GM8 V6 engines suffered with inlet manifold problems that could leak water into the sump. I will probably do a post mortem to see what's happened when I get time.
Had a moment on the Trans am today,modified the waste gate so when it finally gets on the road I can adjust the pressure,perhaps get 9psi as the brochure led you to believe in 1981
No i don't,,,It has the 3 lights in the hood bulge, one is always on and the other's i believe illuminate around 3/4 psi and 6/7 psi. Once its in a position to be driven i will Tee in boost gauge and get it as close to 9 psi without destroying a 41yr old engine. I realise to some reading this that the figure's are somewhat low but remember this engine came out in 1980-1981 and was fairly advanced