Brake servo

Isn't there a boss (possibly still undrilled) on the inlet manifold itself? Possibly the branch that feeds the front two cylinders.

Yes, on the top, where you said, but he may have trouble raising a vacuum because of the emission control. He can block the emission control pipe under the carburettor or maybe even fit the servo pipe to this if he doesn't drill and tap the manifold.

Martin

There are 2 different manifolds for servo and non servo vehicles. I believe the servo one is tapped and has a big pipe nipple right on the top of the manifold.

and on my 2.5 90 it's on the branch from No.4 cylinder if I remember correctly. Certainly at the back of the engine bay. Perhaps you need a new exhaust manifold too?

I think it is right next to the carb on the 2.25.

I had to drill & tap mine to get the vacuum. Best done with the manifold off, otherwise you have to take extreme precautions to stop ally swarf from going into the pots.

I've found it, staring me in the face actually, what looked for all the world like the head of a mounting bolt is actually a bung in the pre-tapped hole in the manifold. Thanks to all for pointing me in the right direction. Greg