Can the heads on a 1992 XJ-S V12 be removed with the exhaust manifolds still attached ?
Yea, I don’t see why not.
Definitely can be. More often than not how l do it.
It’s difficult to do it any other way, as it’s tough to get at the manifold bolts on the underside in situ. Note, though, that the manifolds will probably run into the structure. You’ll probably need to loosen the motor mounts and jack up the engine a tad.