ajusting the boost

[riviera]

I have an 87 with a front mounted percision intercooler with a t63-1 turbo and 42 lbs injectors I bought the car this way. the guy I bought it from had it set to 24 lbs of boost I want to lower it to about 12 to 15 lbs of boost but my only problem is it don't have a boost controler he said I could ajust it with the wastgate rod but he wasn't sure if u screw it all the way to the left or right (facing the fron of the car looking at the motor) any help would be great also do anyone know what kind of power my set up should be putting out the last owner said about 500 on 100 oct. Gas it fells sronger than that thanks a lot for any insight

 

[626gn]

Lengthening the rod will lower boost.