I pulled up a jetting chart for this 90mm plate system I have for my 05 cts-v, the chart reads @55 psi but my fuel system runs @58 psi, I do have an adjustable regulator so I could dial it back to 55 psi, but I would rather leave it at 58 psi, is there a formula to figure out jetting or should I just use the jetting chart at 55psi while using factory 58 psi?

 

3psi want make a difference. Normal ls stuff runs around 53psi with vaccum to the regualtor

 

You'll have no issues running the 58psi using that jetting chart. I've got too many friends doing it with no issues at all.