I own a 92 940gl, 2.3 red block. I found a wrecked 2006 xc90 with the 4.4 v8( B8444S) for $1200. How hard will it be to swap this engine into my 940...

 

Pretty hard. Skill level 10 on the Ten Scale. But nothing is impossible.

 

It is going to cost you more than $1,200. You are going to need to also replace the transmission and your differential might not be able to take the added torque. The wiring is going to also need changes and your front suspension might need to be improved.