Originally a BBK fuel pressure regulator was purchased. As shown (left center, annodized blue), it was too large and interfered with the inlet manifold of the supercharger. The stock regulator clears the manifold, but, is non-adjustable. After much searching on the Internet, it seems almost all aftermarket adjustable regulators have the same large shape as the BBK unit. However, a Mallory regulator (part 4213) was found that appears to have a shape that will clear the blower. Here are the stock, BBK, and Mallory regulators side by side.
Unfortunately, five modifications were required to the Mallory regulator to allow it to clear the blower. In this picture the first three modifications are shown: (1) redrilling one of the cap mounting holes so that the cap can be rotated to move the vacuum port away from the supercharger inlet, (2) removal of the adjustment lock nut, and machining a tapped hole for a set screw (shown in black), and (3) trimming the brass adjustment screw about 1/4 inch shorter.
After installation, it was found that the fuel pressure gauge port is in a poor location, since, once the pressure transducer was attached, even with an elbow, it interfered with the supercharger inlet and EGR valve. Modification (4) then was to plug the existing pressure port and drill and tap a new one on the opposite side as shown. However, now, one of the regulator cap screws causes a slight interference with the supercharger inlet, preventing the supercharger from seating properly on the lower intake manifold. Again we removed the supercharger and make modification (5): a countersunk hole in the cap for a flush mount machine screw. Finally, everything fit, but, it sure was tight!