It's not too terrible (not too easy either). Most of it is pretty straightforward. I searched aroud quite a bit and didn't find a kit to put one in a Chev. The biggest issue you will need to deal with is the Cummins with fan and fan clutch is too long for the engine bay. You can make it fit by using electric fans, but in AZ, pulling loaded , on a hill, it WILL heat up. I am putting a 5.9L 6BT in a '72 Suburban, and I am going to section a chunk out of the core support and move it forward 2.5". I have the room to do this and still have room for the intercooler. I am not sure if this is possible on a later model such as yours. Another issue you will run into is keeping the motor low enough. I was told that I will need a body lift (Iwon't do this), but if my measurements are correct, I can shrink/modify/reinforce the forward x-member (the one your proportioning valve is mounted to) and mount the motor a bit lower in the chassis (the balancer will hit this by my measurements). You may have to make your own engine x-member. I made a new one just to not have to deal with modifying the factory unit. If you shop around, you can find appropriate mounting devices to mount your GM alternator on the Cummins. Your hydroboost will hook up to the Saginaw pump on a Cummins from a Dodge. The big-ass four core radiator that you probably have already should keep the Cummins cool if it is in good condition (and providing you use the belt driven fan/clutch). Intercooler plumbing is going to be a custom affair. A good exhaust shop should be able to help with this if you need assistance. For ease of servicability I would recommend going with a complete Cummins/trans from a Dodge to keep things "simple /forums/images/graemlins/rotfl.gif". The preferred units are the 94-97 Cummins out of a Dodge because they have a wastegated turbo housing and the Bosch P7100 injection pump.
That is about all I can think of now, but it is rather late. If I think of anyting else I will post back. Feel free to ask away, any questions you might have. I haven't actually installed the motor yet, but hopefully real soon.
Good Luck,
Nick
I will try to forward some links to you next week from my 'puter at work about this conversion.