Default 7531plus boost retard help

I have a blow thru carb setup with a 7531 plus ignition, 3 bar msd map sensor. I cant get it to retard timing i set the total timing at 30deg looked at the psi gauge on the graphview it said 14.25 psi so i added 2deg to start pulling 2 deg per pound. I even applied 10 psi to the line going to the map sensor still no retard on graphview or with timing light on balancer. what am I missing ? any help appreciated 1SG Wages (new combo)