DC9-30 DISPATCHER FOUND THE ACFT MAINT RECORDS DID NOT REFLECT THE ACTUAL ENGS INSTALLED ON THE ACFT.

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ON JUL/FRI/02; ACFT X CAME OUT OF 'C' CHK WITH BOTH JT8D-9A ENGS. PRIOR TO THE 'C' CHK; ACFT X WAS CONFIGURED WITH MIXED ENGS AND WAS PERFORMANCE RATED WITH JT8D-7A ENGS. THE ENG CHANGE FROM MIXED TO STANDARD CONFIGN WAS NEVER COMMUNICATED. ON JUL/WED/02; DURING THE DEP TAXI OUT OF ZZZ; THE COCKPIT CREW REALIZED THE PERFORMANCE INFO THEY HAD WAS FOR JT8D-7A ENGS; WHEN IN FACT THE ACFT HAD JT8D-9A ENGS. THE CREW IMMEDIATELY CONTACTED DISPATCH AND MAINT CTL; AND THE FLT RETURNED TO THE GATE AND THE ACFT WAS TAKEN OTS UNTIL ALL APPLICABLE CHANGES IN PERFORMANCE SPECS AND COCKPIT INSTRUMENTATION COULD BE MADE. DURING THE TIME THAT ACFT WAS IN SVC BTWN JUN/FRI/02 AND JUL/WED/02; 5 INDIVIDUAL FLTS WERE COMPLETED. I RELEASED 2 OF THE FLTS. THE CAUSE OF THIS PERFORMANCE DISCREPANCY WAS CAUSED BY TECHNICAL SVCS' FAILURE TO COMPLETE PAPERWORK AND CHKLISTS TO REFLECT THE CHANGE IN ENG CONFIGN. TECHNICAL SVCS REMAINS COMMITTED TO FINDING AN EFFECTIVE SOLUTION TO ENSURE THAT ENG CHANGES ARE RECORDED AND COMMUNICATED IN A TIMELY MANNER; AND DISPATCH REMAINS COMMITTED TO ASSISTING TECHNICAL SVCS IN EVENT MAY POSSIBLE.