First 1/4mile pass with new build

What injectors are you running?

If you only hit 55psi with a locked 3rd to od shift and you can hit 75psi on the street something is definitely off. Throttle linkage, fuel shut off, etc. I would assume it's not a boost leak as that was clean as can be up top. But it doesn't hurt to check. And yeah those injector are tiny for those chargers. Any step up injector wise is going to knock your socks off.