Hans, with my first set-up with stock pistons I used the stock waste-gate actuator from the Buick V6. I believe they were set at 7 pounds. Never a problem on the street but at the drags the boost would continue to climb with waste gate wide open. Probably because of bigger engine and running to 6000 rpm. Saw 12 pounds once before pistons broke. I used a Jacobs ignition retard that retarded ignition the amount I dialed in starting at 3 pounds boost. I also used water injection. Still broke pistons. The present set-up uses the same waste gate actuator but with no ignition retard or water injection. I have never really stood on it for an extended time. Have seen 5 pounds boost with no detonation at all. The lower comp pistons seem to do the trick. Also my 27 roadster weighs half what the 65 Rambler I had engine in does. That may be a big help too. Mike
