Advancing the ICL will fool the motor into thinking it has a smaller cam , considering most cams have more duration than necasary (big is not always better) , then in most appliications advancing the ICL will yield more power as the motor will build more cylinder pressure.

I advanced the ICL 8* (108 lobe sep)& went from a 1.6 to a 1.5 60ft , fitted another cam (112 lobe sep) on the assumption the 108 lobe sep was dumping most of the nitrous out the tailpipes @ overlap , picked up another 2/10ths & got me into the 10s.