GM prom code

[Paul Bjorn]

Can anyone tell me how to work with the hex code that is in a stock GM PROM,    such as the one used in a 1991 Firebird, ECU part no 1227730 ?. I have a Prom   reader, and have downloaded the data. I need to find out what locations in the  Prom control what, with intention of modifying fuel and spark parameters to     accomodate modifications.
Also, when viewing a stock GM calpak, there are 3 chips mounted on a plastic    carrier, I know the 28 pin unit is the Prom, but the 14 and 16 pin units remain unidentified. RAM maybe ? 
any help is greatly appreciated

Thanks
Paul Bjorn