- Original burstproof pillars and the factory rear seatbelt mounts so it definitely an Aussie Clubby or a very late Mini K. 71-78
- Big tunnel bulge for the rod-change, so that puts it at 74-78
- According to the shape of the cutouts at the top of the side box (the former ashtray hole) this car did
not start life with inertia reel belts. Interia belts were fitted 75-78. (See note* below)
Hence I'd date this shell as 74 or early 75 clubby.
*The ashtray cutouts in the top of the side boxes are parallel to the seat crossmember in cars that had an ashtray there. If the car started life with inertia reel front belts the ashtray cutouts went parallel with the length of the car, or 90 degrees to what they do on your shell. This is because the seatbelt reel was mounted inside the side box and the belt exited through the realigned former ashtray hole. This is only Aussie shells, UK were different again.
Hope this helps,