Whilst I adore the D jet setup, and I've converted 120 series cars to injection I really think that given the price now of some of the failure prone parts it isn't a sensible solution, other than if you have considerable D jet experience. Even then, I have, and I'd probably go aftermarket injection if I was to do it right now.

The argument that injection is more reliable than an SU is just plain ridiculous. I prefer injection, it runs properly from cold, it's capable of delivering better economy, but no way is an SU unreliablel, and properly set up it performs exceptionally well.

If you want to do it you need the compete injection set up, you need to change the tank, else it won't run properly below 1/4 full. So that's Loom, tank, injection pump, pump relays, air idle valve, distributor, Aux air valve, head, injectors with relief valve and rail, both manifolds, throttle cable, ECU, thermal timer, MAP sensor, throttle position sensor, and some means of air filtration. Then there's the fuel return to the tank and some stuff I've probably forgotten.