well there are 3 reasons: money, originality and availability.
- to get a running lump would be anything from £800 to £5K plus delivery
- would like to keep the engine and body numbers matching
- carburettor versions of the V12 are hard to find. the heads on the injection models differ so I'd need to transfer my top-end to a block from an injection model and there is a high chance I'd encounter same issues on another engine. the heads are notoriously difficult to remove which is how this all started