[Stootz01]

I picked up a used block last month from a guy who bought it from another guy and so on... He gave me the PCM but I do not know if it is an OBD1 or OBD2. There is a half ripped tag on it, but only a few numbers. Any other way to tell which is which?

 

[shoebox]

Post a pic of what you have. There might be enough to tell.

 

[bobdec]

w/o any label info I do not know a way to identify it from the outside, the shell, connections, and pins are identical (both have all pins in the connectors) . As Rob said in post #2 there may be some info on the label. If you have the Broadcast Code (BCC) piece of the label it's a 4 letter code starting with a 'B' that may help. assuming it's LT1 with 4 connections (blue,black,grey,red) If you have OBD1 and OBD2 scanner capability or software and a cable you can always install it and see with key on / engine off which interface connects.

 

[wdmickjr]

My OBD1 LT1 PCM is 16188051. if that helps.
a GM dealer could also tell you.