magnum manual swap
There was someone on here selling their '73 Dart with a stick and they used the Magnum intake and such with the Megasquirt EFI system. You'd need the whole engine, then buy the kit, then wire it up and tune it. I think the website for it is:
www.diyautotune.com
I know there's guys on here who've used it, and if you have some desire to learn, the setup can be made to work with the big parts (intake with injectors/throttle body, sensors, distributor, etc). Hope that's at least somewhat helpful.