The other allen-headed screw on the Aeromotive regulator below the vacuum line, I was told, was for a fuel pressure gauge. BTW, on my car the vacuum line and the EGR valve try to occupy the same space so don't get discouraged. You may have to buy a section of vacuum line to replace the one going between the stock regulator and the intake, the stock one may not reach. When I had stock injectors, I had the fuel pressure set at 38 psi with the vacuum line in at idle, seemed to run best there. Good luck.
John
__________________
John
1992 Mustang LX 5.0-Powerdyne BD-11A, 3.73's, FRPP clutch, chrome Ponies, Mac headers, Aeromotive regulator, MSD 6A, MSD BTM, FRPP 42# injectors, Pro-Flow Air Optimizer, Trick Flow Track Heat intake, Edelbrock 75MM TB, AFM Power Pipe