2001 Chevy S-10 died after head replacement

I recently had the head replaced by wifes uncle. When he started it up after putting it all back together it ran fine, however it was shooting antifreeze out of a pinhole in the radiator. The hole has been thier several years and never caused a problem so I figured that the old head must have been warped and that the new head increased compression. It wasnt leaking enough to cause worry so I went ahead and tried driving it home from his house. I made it about 3 miles through town at 30 mph. Then when I got onto the highway about another 2 miles I started hearing a intermittent screeching when I accelerated and the truck started losing speed. When I pulled over it had gray smoke rolling out of the tailpipe. I turned it off and checked underneath and thier was no leaks except from under the radiator, and thier was plenty of antifreeze left in the radiator and resevoir. I was able to crank it and get it started one more time. I shut it off and that was the last time it started. The temp gauge wasnt even up to norm, however the engine was to hot to even touch. And thier was steam coming from the back of the engine for a short time. It will crank, but will not start. Any ideas would be appreciated as Im already $500 into this thing I cant start throwing parts at it. The man who put the head on it looked at it and said he thought it jumped time. And is saying that it is probably the computer that caused it, but thats one heck of a coincedence if you ask me. I dont believe that the check engine light came on at any time during the trouble. Please help.