Turboman
Mab An Gov
It tells you. You have a 3 stud manifold, you know what fuel tank you have, and you must know if your vehicle is pre 1974 or not.Paddocks don't seem to sure as to which will fit from these Land Rover Series 2, 2A and Series 3 - 109 inch Mild Steel Full Exhaust Systems - Paddock Spares If they don't know I aint got a clue
Incidentally, I had a look at the Series this morning, and there are brackets, or at least the top part of exhaust hangers, welded on to the galv chassis. The brackets held on with rivnuts were on Nineties.
The top part of the hangers is like a little stub of metal with two bolt holes, sticking out of the chassis rails. if you can locate those on your chassis, that will give you another clue as to which exhaust to get.