Dead 1998 V10

I bought a not running 1998 2500 4x4 with a V10. I was told that the motor was blown in the unit when I bought it. After a couple of hours of fooling around I got it started, it did not sound like it had any internal problems. The idle was alittle off, and it had miss when I reved it up. When I shut it off to change out the oil and put in new plugs, I could not get it to run again. It lost all of its compresion; still has spark and fuel pressure. When I look at the rockers from the oil fill hole, they are not going up and down as the piston moves.
My thoughts lean to a timing chain problem. I have never had one of these beasts apart and could use some insight from a traveller who has been there.

sounds almost like a sheared key, or, as dumb as this will sound, there were a couple of v-10s that broke the crankshaft just behind the first couple cylinders. The engine might run if everythign gelled, but otherwise, you could crank it over, and the front of the unit, along with the timing set wasn't moving

Strange occurrence indeed. Let us know what you find

Did you take it down the road for a ride and make it pull when you got it going?

Took the front of the motor apart today, and found that the bolt on the front of the cam holding the top gear had loosened. When it loosened the sprocket key sheared. The cam and gear must have alligned on what was left of the key and wedged together in passing one another, allowing me to start it. When I went to restart it, The allignment must have shifted again.
Should be an easy fix from here on out.
Could use some help with the timing set up :) of the gears and chain. My Dodge book is useless when it comes to V10's. I also had to build a special puller for the harmonic balancer. That baby was really stuck on.
The books say that all 1998 truck V motors have a chain tensioner. Not so, this one must have missed that part of the assembly line.

Good call on the sheared key!!!!!!

Thanks for the help.