Lee --

This may not be a helpful answer, but....... you certainly do not have to pull the engine!! At worst, you'll need to pull the manifold & turbo out -- which is no small task (but nothing like yanking the motor!). That's how I fixed mine ('82 240), but I had some broken-stud-drilling to do.

The next question is: Can you pull the manifold & turbo back far enough to sneak a manifold gasket in? I'd bet not. The oil drain tube has only limited range to move (so maybe you pull it), and there's very little clearance between the turbo and inner fender.

One possibility might be to unbolt the right engine mount and rock the engine over an inch, or so, giving you more working room..... Watch you fingers.

I'm positive other Bricksters have developed clever soultions for doing this.

However you approach this, if/when you remove the hoses remember to block off the turbo inlet and outlet (duct tape) to keep that missing nut outta there.