454 Timing Issues?

[savatreatabvr]

I came across a timing light at a yardsale so I checked the timing on my mid 70's 454, the harmonic balancer timing mark wasn't on the tab on the timing cover! I adjusted the distributor to where it's at about 10 degrees BTC now but it idles low and doesn't seem to have done much for performance! I'll adjust the idle screw and mess with the air/fuel mixture tomorrow but now my question what is the manufacturers timing specs on a 1976 stock 454 with HEI distributor? I've found online it vary's from 4 degrees to 16 degrees depending on who posted the info!