I'm curious about your pump pressure.. I'm running a Borgeson pump in a Hemi swap, using a stock Hemi 6.4 pump. I picked a pressure reducer form Sublime, that reduces the pressure to 800 -850 psi. I believe stock pressure is 1350 psi (still trying to find more data) The lower pressure valve is intended to be used with a stock box, no mention of aftermarket. SO, I'm kinda torn which way to go, since the recommended pressure for Borg is 1100-1250. What pressure are you running?
I also noticed on his site that he also recommends running a 2.5 gpm orifice.. Again, not sure how any of this applies to the Borg box but maybe adding a 2.5 orifice to you setup may make it feel better for you. I'm still trying to figure which direction I need to go...
From
Sublimeparts.com site
These pressure relief valves are designed for 800-850 psi and are a direct replacement for the valves in your current "Toyoda" power steering pumps as found on most Hemi engines.
Simply combine with a 2.5 Gallon Per Minute (gpm) flow orifice and you should be good to go.
We recommend using the TurnOne 2.5 gpm orifice fitting, commonly found for the Cadillac CTSV.