Not another fuel injection question

[Awjunkies]

Yes this is my second thread in 10 minutes!! Yes I did a search but I'm looking for personal experience with kits and what not.

Here is my dilemma, the project I'm picking up is a 70 k10, AC barn door burb. It has a newer rebuild on it so I feel it would be a waste money wise to pull the 350 out of it. Downside is that it has a 3spd column shift and I ultimately want a 4spd. I'm not looking for a high horsepower vehicle just one that gets "better" gas mileage. Now don't scoff, but if I can get 15mpg it's a lot better than 10...

Looking at the price of current efi kits and the price of buying a "good" 700r4 it makes sense to find a used LS/4L60 combo? My whole thing with that is the gamble of putting in a tired motor just to have spend time and money on an untested motor.

Thoughts and opinions are greatly appreciated. Take the plunge and drop in an LS or go with the 700 and fuel injection kit. If it's the FI kit what do you recommend, I see them go from $500-3000. Understandably the lower prices ones will need everything to go with it and I'm looking to purchase a plug and play system.

Before the quadrajet guys chime in I need to add that I need a get in and go vehicle. Can't really expand more on that unless you want to message me.

Thanks in advance!