I found this eaton m112 sc on craigsl. Http://delaware.craigslist.org/pts/2346476708.html. .. Will this work on an 04 4.0 xlt with about 75k miles?

 

yes it would if only you had about 60k miles

 

I didn't notice the thread started last fall where someone put one on. Any idea of the engine work needed to not blow my engine?

 

well, you have to make a custom lower, and the needed parts to support it, then tune the engine, and keep boost under probably 8psi max if you're not touching the internals of the engines.
A Guy makes a kit to put an M90 on a newer 4.0 engine...RP Caster, look it up.

 

8PSI is even a little high. I wouldn't go above 5PSI unless doing head gaskets is your new favorite hobby.

And other internals will need replaced prematurely.

 

yea im not building a race vehicle of any type out of this truck. i just figured 500 wasnt a bad price so why not do it

 

500 for a M112? that is cheap! I picked up my M90 off a supercoupe for $66, along with all the plumbing and intercooler.
I talked to Ron Caster (the guy who makes the kit for putting an M90 on a 4.0 SOHC) and he says he is currently developing a kit for the M112. He didnt say when itd be done but it might be wort hwaiting for.
And also, if you buy a water/methanol injection kit, you can run a few more lbs of boost