75/96/.90 low boost #s

So i am running a 75/96/.90 t4 on my 6.7, has a cam and ported head and is fueled by some 200% overs. The issue is, regardless of tune i can only make 40-45 psi and it never cleans up.



So where could i look to try and improve perf from this unit. Drive to boost is never over 1:1



Thanks

pulling my hair out trying to get thus thing to run better.