1970 Duster AlterKtion, 4 Link, LS/T56/Turbo and Minitub

TT5.9mag said
No not at idle. It’s 40ish at hot idle. 70 psi through a run. It touches 80psi at the top of the pull. Yes this is the pump gas twin turbo deal for my boat.
I wasn’t aware of the gm mls exhaust gaskets that’s good to know. What their OE application?

All of the trucks I've taken apart like early 2000s are MLS. I think all of the LS exhaust manifold gaskets are MLS, but I could be wrong there.