[TC]

Personally,I'm not a big fan of electronic fuel injections...for several reasons.
The biggest being,there expensive to work on,difficult to diagnose,and require a lot of expensive/specialised tools,if you plan to work on it your self.
Plus,your more limited to what you can do,if you want to make some more horse power...unless price is no concern.
Also,*in my opinion*...I don't think they offer all that much over a carburetored engine,in most cases...other than turbo applications.

It's a pretty tuff question to answer,without knowing what the motor needs to do,what the budget is(if there is one),and what gears/trans/weight of vehicle is...ect.

But,if the most bang for the bucks the plan,I would defiantly go with the 350 sb.There generally easy to find parts for,and prolly the most economical engine to play with.If fuel injection is an absolute must,a TBI might be an option too.