Use the search function to find and save threads on this conversion. It is able to be done subject to your local jurisdiction laws.
The things you will find out by researching on this forum will allow you to form an action plan.
From what I remember to swap to a TD42 from a TB42 you defiantly need then TD42 bellhousing and starter motor, alternator with vac pump and the vac lines including vac tanks and one way calving.
Obviously you need to keep the TD42 donor engine’s entire engine ancillary items as they are unique to the Diesel and not the same as the petrol.
The TB42 fuel lines should suffice but the filter and engine bay lines will have to come from the TD42 donor as well.
Electrics are easy to modify and fabricate, however th alternator fed tacho signal in the TB42 dash will not accept the information from the TD42, the original TB42 signal is sent 3 times per revolution and is resisted. So you’ll have to research that or fit an aftermarket generic alternator clamp tacho kit as I have done. The aftermarket setup takes a signal from an externally mounted sender you clamp on the alternator, and the tacho is then tuned to the correct RPM using a timing device. The Tacho is then mounted on the dash.
