The Mk I 948cc Sprite has the same flywheel bolt pattern as the Morris Minor (also 948cc), also the same clutch bolt pattern for the small 6.5" clutch. The Mk II Sprite, also 948cc, ditto.
948cc flywheel

The Mk IIA Sprite and Mk I Midget, 1100cc, also have the same flywheel bolt pattern, but have clutch face and bolt pattern for the larger 7.25" clutch plate.
1100cc flywheel

The Mk III Sprite and Mk II Midget have the same clutch bolt pattern (still 7.25") but a larger diameter flywheel bolt pattern.
1100cc MkIII Sprite / MkII Midget flywheel

The flywheel on Mk IV Sprites and Mk III Midgets, with 1275cc engines, are held to the crankshaft with 6 bolts and two off-set dowels. The flywheel will fit in only one position. The clutch plate is only 6 5" but it uses a diaphragm pressure plate, not a spring plate as with the earlier cars.
1275cc flywheel

Therefore, if you need a stronger clutch on a 948cc engine, you can achieve this in two ways...
  1. Fit the flywheel from the Mk IIA Sprite. It will bolt straight onto the crankshaft, but it will accept the 7.5" clutch from the 1098cc engines.
  2. Use the 948cc flywheel, but have the face re-drilled to accept the 1275cc diaphragm pressure plate. Note: this is a precision job not to be attempted at home on the work bench.