Chevrolet Repair: timing chain failure

Question
hi.i have a 2003 gmc sonoma with 91k miles (bought it new).timing chain has broken.interference or non interference engine-everywhere i check i find a different answer.was going about 45 mph when it broke,kind of coasting,not on the gas hard.what are the chances of valve damage?so far i have heard 50/50 from different mechanics.no one seems to know what they are talking about.last mechanic i talked with wants to replace chain,gears and tensioner and see if it runs.what is your opinion on doing this?

Answer
HI JEFF, I AM GOING WITH YOUR LAST MECHANIC..WE HAVE SEEN JUST LIKE YOU WERE TOLD 50-50 ON THIS..HOWEVER IF YOU WANT TO KNOW BEFORE YOU DO A TIMING CHAIN,REMOVE THE VALVE COVERS AND
REMOVE EACH ROCKER ARM FROM THE VALVES AND DO WHAT IS CALLED A CYLINDER LEAK DOWN TEST..WHEN THE VALVES ARE CLOSED PER EACH CYLINDER YOU ARE CHECKING YOU PUSH AIR INTO IT AND CK FOR A LEAK EITHER IN THE EXHAUST OR INTAKE..IF NO LEAK IS PRESENT BY AIR DROPPING DOWN ON THE MACHINE OR YOU DO NOT HEAR ANY AIR ESCAPING IN THE INTAKE OR EXHAUST THEN THE VALVES ARE FULLY SEATED AND NOT BENT. BUT WITH THAT BEING SAID THIS TAKES SOME TIME TO DO,,MOST TECHS FEEL IT IS FASTER TO CHANCE TEARING DOWN THE FRONT OF THE ENGINE AND PUTTING A NEW CHAIN AND GEARS AND SEE IF IT FIRES..HOPE THIS HELPS YOU AND GOOD LUCK,,,TOM.