Adjustable cam gear?

[shelbyturbo1989]

I'm thinking about getting an adjustable cam gear. I have a 1989 shelby daytona and right now i go through the traps at about 102 mph to give you an idea of the hp I'm making. I'm going to try and get a few more miles per hour so that i can break into the 12's cause i'm really close. The head has been shaved about .030", and i know that that changed the timing. If I were to invest in one of these, is it going to make a noticable difference?

Thanks guys.