Right. If you want to do it correctly, this is the way. Maybe we can start a little easier. The engine number and maybe additional information are stamped on the bridge over the starter motor. Fairly easy to access on the E9, much harder on the E3.
@sfdon has posted a guide somewhere here. If my assumption is right and your engine retains its original block, both unsure, your car will have a 3 litre engine, carburetted from new, built in 1976.
This means the block will not have the size cast in as in <6603F3D9-DFBD-4565-8E8A-5EF2F09272BE.jpeg> but probably stamped near the engine number. It should have the six pockets on either side for the large crankshaft, some of them visible in the same picture.
Of course, the numbers would give only the original setup, not the present one. But it's some kind of start.
Information about the South African E3 CKD is scarce, this includes the BMW Group Archiv in Munich. I spoke to a gentleman there; they will address it when they have time but they are always overworked.
