i have a 06 brute force with a blown engine. I bought a 08 efi motor that was full built for to good of a price to say no. What needs to be swap from my old motor to make this one work.

 

You'd need the computer (eco, ppm, etc) to make the fuel injection work, plus any sensors, or convert the new motor to run the old carburetors. I might be inclined to swap the carburetors back on. I can tune CV carburetors, I can even tune my fuel injected Dodge Hemis. Wouldn't know where to start with a Kawasaki BF.

 

There are bound to be some differences in the wiring harness between a carb and an EFI model.