Okay, so i could be wrong here. And proabbly am
But i did some research. It sounds like the "Powershot" plate is pre-set to 125 hp. Non adjustable. I guess its already drilled to flow that much and you dont need jets.
PLEASE CALL HOLLEY AND VERIFY THE ABOVE INFORMATION
But if thats true, then you're kind of stuck. I looked at your picture and it does look like an old powershot system.
Further, looking at the manual for a powershot system. It does not list any jetting tables, or even jetting included with the kit.
So im assuming the above is correct.