91 GMC C1500 Ignition Timing
 

I got a 91 GMC C1500 with a 5.7L, W/AC, without an air pump & a 5 spd manual trans. My emissions label from under the hood is missing, so i don't know what to set my ignition timing to. And i can't find any info in any service manual, they all say refer to emissions label located under the hood, like i said mine is gone. If anyone can help please let me know, Thanks
JP

0*, then the computer controls it from there

No. 6-8btdc, the computer can only work within a range. Set it with the EST disconnected, brown wire with a black stripe over by the heater box.

0 is what my stickers say .

My hanes book says '0' & I just did mine. Like ColinOpseth said you have to have the EST disconnected to get the correct reading.