Pontiac Repair: 1997 GRAND PRIX GTP, factory specs, engine manufacturer

Question
I INSTALLED A SET OF 1.9 RATIO ROCKERS ON MY STOCK L/67 SERIES 2 THEY WORKED AWESOME !A FEW MONTHS LATER I REPLACED THE ORIGINAL ENGINE WITH A COMPLETELY REBUILT 3.8L LONG BLOCK FROM REPUTABLE ENGINE MANUFACTURER !I INSTAKKED THE 1.9 ROCKERS ON THE NEW ENGINE WELL THE NEW ENGINE HAS NO COMPRESSION VALVES WONT OPEN ! WONT START ENGINE MANUFACTURER SAID IT WAS REBUILT TO FACTORY SPECS HAVE NO IDEA WHY WONT FIRE ! WHEN I REPLACED ROCKERS WITH STOCK ONES IT RUNS FINE EVERYONE IS STUMPED ON THIS ONE !!ANY IDEAS WHATS GOING ON WOULD BE APPRECIATED THANKS JOHN ! THESE ENGINES ARE SUPPOSED TO BE THE SAME ENGINES FROM FACTORY FROM 97-07

Answer
I have no Idea why this is I think I answered this question a whil back. I do not get into any performance parts at all strictly stock. usually when a car comes in the doe with aftermarket stuff on it and the customer finds out they voided the warranty they don't want it fixed by us any more. For some reason here the increased ratio is keeping the valves openbut I have no clue why. do the rockers need some kind of a shim under them to go on top of the rocket plate on the motor? This question is better suited for whom ever the part manufacture is then for me to answer you I'm only guessing.