EFI Bung in head update

Ya'll are talking about the Corvette fuel/reg. Many EFI modders use it because for $20 (O'Reilly's) you get a 56 psi reg with your fuel filter. True "return-less" means only 1 tube going forward from the tank (fuel pump in tank). That was an EPA mandate ~2001 so gas in the tank didn't get heated by flowing to/from the engine bay. I haven't read of vapor lock problems, since the boiling point of gas is much higher at EFI pressures.

I don't know that it is uncommon for a "pressure reg on rail" (2000-) to be installed at the upstream side, so fuel is dead-headed to the rest of the rail. I have one from a Magnum engine at home. I kind of recall that the supply and return are on the same side of the rail, as in Pishta's. I expect it has more to do with how the fuel lines are run in the car. It probably wouldn't affect the rail pressure. They all operate as "back-pressure regulators", which is similar to a "pressure-relief valve". Most reference the fuel pressure to intake manifold pressure, but the Corvette filter/reg doesn't, so it controls to 56 psig, i.e. relative to atmosphere.

That stainless Northstar rail looks like a good choice. The Magnum rail has a nylon hose connecting the 2 sides, which is a failure point. Nylon fuel hose is used in most modern cars and scares me. They have no clamps and I have read of it cracking over time. Nothing like a high-pressure gasoline spray to make a nice fire. Usually they drip first, so you smell it.

Junkyard diving will save a lot of time and money. For my someday slant EFI plans, I bought a used V-6 rail with injectors (Intrepid, I recall) real cheap. The spacing closely matches the runners on a slant intake, you just slide along till you find the spot. I'm not too worried about spraying right at the intake valves. I don't know that anyone ever proved that is important.