Two issues. Any '89-on 240 with M47 will use the crank position sensor and the heavy stepped flywheel with the peripheral holes. Identical to the non-holed intercooled turbo flywheels from 84 1/2-85 but not ('83 flathood Tic's). Any 740, turbo or not from about '90 on will also use that flywheel. Earlier M47 cars have the stepped flywheel but not the holes. So you need the correct flywheel and the correct clutch kit which will not be at all similar to the clutch and flywheel in an M46 equipped 240. So be carefull about that.
On the good side, pulling an M47 out of a 240 is about as pleasant as a flywheel hunting experience can be. Did a pair of them recently, one for a flywheel for the flathood (no holes required) and on for the auto to manual conversion kit for the '91 245 (with holes). Be sure to get the pilot bearing retainer spring out of one of your donor cars.