I'm building a fuel injection system for my 250 right now. Check out this site for some back ground:
http://www.bgsoflex.com/megasquirt.html I've already assembled and built the controller. I ordered the testing and simulation setup so I can experiment with tuning this thing long before it gets onto the engine. I really don't have a whole lot of money right now and I haven't had time to do the custom work yet in my college machine shop. Eventually I intend to either redrill a stock manifold for injector bungs or create a new manifold out of a select number of machined pieces and sheet metal. This is another great site:
http://www.sdsefi.com/tech.html The piece on building a surge tank is especially nice considering we're going to EFI from nothing at all. You have to consider more than controls, sensors and actuators- there's the rest of the system.
