Rbertalotto,
I just finished doing a valve adjustment on my 98.5 24v Dodge. I have 149K miles on it and the service manual says to adjust valves at 150K miles. It was fairly easy. They didn't need much adjustment. Three or four of them didn't need any and the others may have been about half a thou loose. I followed the instructions put out by this fellow:
http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/26-engine-systems/121-valve-lash-adjustment
I also highly recommend the Turbo Diesel Register forum and magazine. They have really helped me get answers and advice for various problem issues and upgrades to the truck.
Buzz
