I remember reading somewhere that the reason you run less timing is due the increased heat generated by the increased CR. The heat can not get out of the combustion chamber efficiently. This is where ported heads (special attention payed to the combustion chamber) and good exhaust come into play, they help get the heat out of the engine... That article mentioned 8.25 DCR being ideal for street motors with stock heads, 8.5-8.75 DCR on ported heads, both running pump gas... So with good heads and exhaust you should be able to run decent timing...

all that may be crap, i dunno, makes sense but it is what i read...

 

Every setup is different,mine like 24.5-25 degrees N/A with what I got!!No more no less