EFI won't give you any real advantage over a qjet that's setup right, save for better intake flexibility.
EFI has great advantages over a carburetor. The cold-weather drivability is far better, the milage increases, the powerband is flatter and has no flat spots, EFI doesn't need to be rebuilt after 100000 miles, don't have to pump EFI to start it, the list goes on and on.
I am a Q-Jet fan, so I would likely leave it. My 85 Cutlass 350 with a 307 CCC system rivaled EFI for drivability and manners. And 23.5 mpg to boot... (THM200C/2.14 gears) I went to 2.56's and no OD and dropped it to 21.5 mpg.... Even with a 204/214 cam (which was waaay to big for that low compression) mpg didn't drop below 21.5. City held with the 307 at 17.5-18 mpg.
I am a fan of a good worthy project. An EFI Olds V8 307 would be a nice ride. I was looking at a 7747 PCM and TBI to go with my THM200 4R swap to go with my 3.23's. I never did get the time to do it. I have the THM200 4R still, and ended up giving away my 3.23's (7 5/8" too, wish I didn't....)