I have a 90* fitting right off the reg,i used a #2 philps bit inside the fitting(wont go thru the 90* bend)

it restrics it down at least 75% i would think.

with out it,it has no psi on that side and free flows,it does keep 5 psi on the other side, but not sure when driveing as I cant see the gauges

last one I saw converted with the stock intake pump had the regulator from RobbMc it was a deadhead or by-pass unit,,not sure if its fits your budget though

I also have one of those purolator regs that has a hand dial and is 5/16 outlets with hose barbs.

not sure if it would handle the intank pump