TKOPerformance wrote:

Sure, just find a regulator with a port for a return line.  Aeromotive makes a bunch like that, though they are certainly not cheap.  Not sure where you are looking to be cost wise.  

Ok Thanks. So anyone with return will bleed off pressure between regulator and carb after shut down. i was looking at  a Holley 12-881. Have the wix filter 33040 with the 1/4" return but thought regulator with return would be cleaner looking.

boss347convertible wrote:

I don't profess to be an expert on fuel pressure regulators and my experience with them is limited to pressure regulators in conjunction with carburetors. My recollection is that when the fuel pump stops pumping, the pressure regulator bypass valve will close, thereby preventing fuel from returning to the fuel tank.  That said, if there is residual pressure in the line, the regulator will not act as a relief valve unless the pressure exceeds the set bypass pressure on the regulator. I don't think a pressure regulator will solve your issue. Many mechanical pumps have a check valve (anti-siphon) built in. You can purchase electric pumps with and without a check valve. 

I have not disassembled a pressure regulator in over 25 years, so the above could be entirely wrong. Hopefully, someone with a better understanding of pressure regulator operation will chime in.

Thanks for the reply, that's what I found when I researched it , so I posted the question on here.. If it is right then my only good option will be the Wix 33040 fuel filter with 1/4" return that you install between regulator and carb and run return 1/4" line back to tank

A bypass style regulator also needs a return line to the tank.  That's what it does with the excess fuel.  Installing the regulator is easy, but the return line part would  be more involved, though most guys who have done an EFI swap have had to figure this out too.  Many I think have just added a fitting to the filler neck for the return.  

Are you running a carburetor heat insulation or phenolic spacer?

My Edelbrock 1406 carburetor would boil the gas in summer heat when it was directly mounted to the Performer 289 intake manifold.  Could hear the gas percolate in the carb after shutdown.

The installation of a 3/8” heat insulation spacer was my solution.
No pressure regulator with my setup.

My two-cents.  I would check fuel line routing, carb spacer/insulator (as Nos681 suggested), install a fuel pressure gauge to verify what is happening.  From my experence, mechanical pumps do not require a regulator.