Well, one thing for sure, the exhaust manifold studs are always a problem from the heat cycles and rust. Better start putting the liquid wrench on them way before you need to un do them.

The immediate danger would be if you smelled exhaust and were breathing fumes. Eventually it will burn up the manifold though and then it might take two gaskets to fit tight (I had that problem with a 230 ci 6 in a camaro).

\'59 Chevy 1-ton
'72 c-10 (in progress)
The Great Rust(less) Mountain
\'47 Jeep cj2a