What should the timing be on a 1993 gmc sierra?

[sniperlif3]

I have a 1993 gmc sierra that has a chevy 350 small block on an automatic 2wd transmission. I have the truck running currently as close as i can to 0* (when the ECU is not changing the timing). I am just wondering if there is any other particular timing amount that i should have that would be better since 0* is what is rated from the factory