cuda71ss

I am looking at buying a fuel pressure regulator. Only the 12-803 and 12-803BP are mentioned here on thirdgen so thought I'd post and get some input on some others very similar. Writing this as I'm on the phone with Holley trying to get a product recommendation.

12-803BP
https://www.holley.com/products/fuel...parts/12-803BP

12-881 (chrome - they have 12-887 which is the same internals, but a black finish)
https://www.holley.com/products/fuel...s/parts/12-881

12-879
https://www.holley.com/products/fuel...s/parts/12-879

So after researching around here, I now understand I need to have a bypass style regulator because I am running the stock in-tank EFI pump from my removed V6 through stock supply and return lines to a stock 350 and Edelbrock 600 cfm carb. Here is where I am confused... I read here from MANY posts people run the 12-803BP. The Holley product support recommended not using it because the return line would still have too much pressure for that regulator to handle. So, he recommended their 12-879 which adjusts from 4-60 psi. Can the thirdgen community straighten me out please? Hopefully others searching for these newer product numbers land here too and quickly get resolution.

Thank you!

sofakingdom

iTrader: (1)

The one most often mentioned around here is the Mallory 4309.

cuda71ss

Oh man! Can't believe I forget to mention that in my original post. Yes I did see the Mallory all over thirdgen.

Question still remains...since I'm inquiring about these Holley FPRs. I just want to hear it from someone that's been here before. Perhaps no one has...won't know til you ask.
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Berlinetta00

The standard holley 12-803 is what I run, but with an external carter fuel pump which struggles to get past 8 psi. With a stock EFI in tank pump, I would think that any regulator designed for a carb would have issues. I ran into the same problem on my 88 dodge that I converted to carb from EFI, even with the same regulator I could not get pressures on either side of the regulator down low enough for the 1406 carb I was running. I swapped the in tank pump to a carb rated one and no more over pressure. I would definitly suggest just swapping the pump to a lower pressure carb unit and going with the 12-803 as opposed to that crazy expensive 12-879, probably cheaper that way too.

lugnut

iTrader: (1)

Did u get this figured out

skinny z

I'm running a Holley Blue electric pump and have tried both of the Holley regulators posted. The return line was essential to keep the fuel pressure stable so the 12-803BP was used. In addition to that, what I had for a return line was too small as the 5/16ths OEM return line was long gone (this chassis was originally an EFI V6 ). I tried the 1/4" vapour line (charcoal canister to tank) however that was too small and fuel pressure would spike. I added a length of -6AN to work as the return and now I can keep the fuel pressure at a steady 5-6 PSI.
The return style fuel system also helped with the vapour lock issue I had been experiencing which was most noticeable while waiting in the staging lanes at the drag strip. The fuel lines (OEM routing) are quite close to the headers and would boil the fuel using a conventional "dead head" arrangement and a mechanical pump.