What happened to my boost??

Hi guys. The weirdest thing happened to me. I had a water leak in my cylinders because of a faulty head gasket after doing a turbo conversion on my car. Boosting 15psi at that time. Took of the head, replaced the head gasket and assembled the whole setup. Now my car doesn’t want to boost more that 7psi even with the actuator closed fully. :screwy: (The exhaust housing was a bit loose too but we did tighten it) No boost pipe leaks. It is so puzzling and frustrating after spending all the time, money and effort to make it worth my while. Please guys, help me out!

How did you confirm no boost leaks?