I think most of the GM motors come with the 10 degree retard on the cam since the use of ECM's and the knock sensers. i can remember back in the 80's the trick for a little more performance was to degree the cam in to "0" for more bottom end. But i would still pull the timing cover and check the gear. I had a friend who had a ZZ502 in his truck, it lasted about 40,000 miles and shelled the gear. It had plastic teeth on the cam gear for less noise, i don't know if they still use them, but i know they have been used since the 1960's, just a precausion.
Zip.