You might want to take a look at Retrotek. They have a fairly new system that installs in place of a 4150 carb with very few wiring additions and no fuel return line. Its going to take a phone call it seems since I've not gotten a response to an e-mail request for more information.
http://retrotekspeed.com/
Interesting idea to say the least and an estimated price of around 2K.
Mike