Connect a laptop running Diacom software and read the ECU information...
That is swell information, but OP only has a timing light afawk. No mention of runnability issues, troubleshooting, work performed or audio warning indicating a fault. We don't know if OP has diacom, access to it or even owns a laptop.
I know that the HVS (flat GM cap) igniton system does not require the operator to check/set timing the conventional way and I'm quite sure you do as well. OP most likely does not know this and is looking for some help. Let's give them some pertinent info regarding their question and leave the esoteric troubleshooting for later if the need arises.
FYI the info you posted from diacom which I guess is from your personal equipment does not indicate a timing spec....
To OP:
The info provided by the previous members is correct, you do not need to check/set timing the conventional way. The ecm does this automatically as long as the distributor is installed and set correctly if/when is has been disturbed. There is a procedure outlined in the oem manual for initial distributor setting if it has been disturbed, however if your engine is running/performing correctly there is no need for this procedure
