Certainly the crank..it is flanged instead of having a tail. So you will need the crank (and rods if different big end journal sizes). Kev will be up later on, he describes the conversion thus from sprite to midget, but I'm unsure what specifically he is describing to the rear main caps:
drmini in aust wrote:
It's an easy job to fit it to a Mini. The bolt holes of the Sprite/Midget sump line up with a Mini or A/A box. I did this with a 1098 AH Sprite motor years ago.
Work needed:
1. Machine the return thread housing bottom half from the rear main cap.
2. Undo the return thread top half from the rear of block block and discard.
3. Unscrew and remove the oil Midget pickup pipe. On a 1098 Sprite the Mini O-ring seals OK to the block there, but check size. If the O-ring is too small to seal, screw a threaded bush in there and make flush.
4. Obtain a 1275 primary gear to fit your crank.
5. Cut the 2 engine mount wings off the front engine plate (not needed in a Mini).
[edit] Of course you need big journal rods to suit that crank, otherwise grind the crankpins down to 1.625" (stroke it too if you want) and use slightly narrowed 1275 Midget or Cooper S rods.