Mercury racing 500efi fuel pressure regulator
 

I have mercury racing 500efi in a 47 fountain. Center engine has too much fuel pressure, 65 -70 psi. Other 2 engines checked out at 40-43 psi. Fuel pressure regulator is very difficult to even get to on the center engine! If you are familiar with the cool fuel system from mercury I was wondering if there is a way to bypass with an aftermarket adjustable regulator? Or a better way to fix this. Thank you