I am not a big fan of diesels, especially their repair bills so I am going to make modest diesel like power using a LQ4 6.0L gas motor.  I chose the Yukon denali because 1. it rides great. 2. came wired for electric trailer brakes and 3. has on board compressor with air shocks to level the thing up once i put the trailer on it. 4. I really like the LQ4 motor for boosted applications.  LQ4 is only 9.4:1 compression ratio which is really too low for aluminum heads although still makes decent power and shocking how much torque it made after programming on it.   Stock these are rated 320hp and 370-380tq.  Made with the 75% drivetrain efficiency for AWD made 320hp and 380 tq stock with that correct factor.  With electric radiator fans it made 333hp and 393 tq so that mod was worth every penny.  I used the factory twin fan setup from a 2005 5.3L truck which dropped right in and yukon even had the bolt holes for it.  i just added the trigger wires to the PCM to control the fans.  I have the PCM wiring diagrams on my website that lists the 2 pins needed to add to the computer to trigger the relay.  I used the GM AC Delco relays D1786C GM part number 19116057.  I initially tried the universal relays but they would fail after a few months.  These seem to work much better and I have them stuffed under that underhood relay fuse box and I have my main power there as well.  Those ECM pins connect to pin 86 on the relay.  Pin 85 and 30 I connect together and I use a 40 amp breaker hooked to main power.  I find these fans use a lot of power when they run but yukon never gets overheated.  then 87 powers the fan.  I use separate relays for each fan and separate breakers that way one can fail and your still ok.  With the old relays, I would notice that the motor got about 20 degrees warmer while at a traffic light or something and I knew I had a relay out.

Now with programming here is dyno graph.