The Stock Regulator
Your stock fuel pump has a relief valve that opens at 64-85psi at zero discharge according to 1983 specs. and along with the spring under the diaphragm that pushes it against the opening in the TB outlet keeps your line under pressure when the pump isn't operating. The std. pressure the TB inlet sees according to 88 specs. is 35-38psi and is measured with the engine running at idle. Your stock regulator is to keep the pressure at 36psi. This is higher than the pressure in the injection mixer so that the pressure in the mixer is kept constant. Inside the regulator is a diaphragm/spring and a vacuum hose that connects the inside of the mixer to the underside of the diaphragm in the regulator that is held down by that spring.
When the fuel demand increases, the spring is assisted via the boost pressure that comes into the regulator through the vacuum hose connection and assists that diaphragm holding back the fuel with greater force so the 36psi is maintained.
There is no compensation of increasing pressure in relationship to a boost situation.
As your factory spec. fuel pump is almost never replaced with a factory unit and is usually replaced with one of greater volume and pressure your regulator has no way to know of the increased output. The spring inside the regulator is the only thing that can and actually does "regulate" the fuel. It's also good to keep in mind that the boost level that is in excess of factory specs. will also raise the pressure past 36psi from that greater assist to the spring. Under most circumstances factory boost levels have been increased by the owner and a new pump was installed. Factory regulator can now no longer maintain 36psi.
WHAT WE DID
First we removed the top portion of the throttle body that includes the regulator. Remove the regulator, pulse damper and inlet tube. We used a rotary cut-off wheel to remove the portion that the regulator fastened to then tapped the hole for 1/8"npt. We got a 1/8"npt plug at Lowes, you must get a npt plug (tapered) and NOT a straight thread plug. We removed the stock plug from the opposite end and tapped that for 1/4"npt. We got the 1/4"npt 90 degree adapter so we could use a 6AN hose fitting. The regulator is a boost compensating type to raise the fuel pressure 1psi for 1psi of boost up to a limit of 15psi over base and that had 6AN adapter fittings. We made the hose same as we did HERE. The 6AN hose=3/8", the stock hard return line is ~5/16" and the 6AN hose will not seal properly to a 5/16" tube so we also got at Lowes a 3/8" barb, 1/4"npt coupling and a 5/16" barb to adapt our new hose to a short remainder section of stock hose to complete the upgrade.
Now we can have a constant pressure in the mixer at a base we decide and have increased pressure for our added boost.
Here are the finished results:
