Modern 318 in a 72 duster.. Possible???
If you have no skills with electronics wiring, then it is well worth it, if you have some electrical ability, then you can do it yourself.
One of the real advantages of a Magnum motor with FI is the incredible amount of torque you will have campared to a caburated engine with the same cam and components. Ina light car, they can be quick. I saw an article years back where they took a 5.9 magnum with a 292 cam and carb, dropped it into a duster with 3.91's and a 727 and ran 12.90's. I think If I remember right, they ended up getting 12.50's with tuning and tweaking.