96’ Vortec carb in 86gmc fuel pump question.

[trapper70]

Hi everyone, I installed an 1996 Vortec 5.7l in my 86’ GMC and am using a carburetor which is working out great. There is no provision for mechanical fuel pump so I am running an electric puralator 3-7 psi pump located near the tank.
I am changing out the tank due to an old repair leaking and am wondering if a pump in the tank is a possibility?
Are the pump mounting flanges for like the 88’ on up the same as a sending unit flange on the top of the tank for 87’ down.
If so is there an in tank pump with the 3-7 psi or will need to run a pressure regulator?
TIA

 

[bucket]

The tank openings are the same, however, the FI tanks have a "cake pan" tray made into them to help keep the pump submerged when the tank level is low.

I'm not sure if a direct fit, low pressure pump is available or not. Personally, I'd run a TBI pump and a bypass regulator. That pretty much eliminates the chances of vapor lock.

 

[Smtty58]

I did a little research on this for mine. So far I have been unable to find a bypass regulator that can take the 16 psi TBI pressure down to something a carb can handle. Looks like most of the regulators are for high pressure EFI systems.

 

[Bloodhound1981]

Why wouldn't this work?

https://www.holley.com/products/fuel_systems/fuel_pumps_regulators_and_filters/regulators/carbureted_regulators/parts/12-887

 

[bucket]

I did a little research on this for mine. So far I have been unable to find a bypass regulator that can take the 16 psi TBI pressure down to something a carb can handle. Looks like most of the regulators are for high pressure EFI systems.

Pardon Our Interruption

 

[bucket]

Why wouldn't this work?

https://www.holley.com/products/fuel_systems/fuel_pumps_regulators_and_filters/regulators/carbureted_regulators/parts/12-887

You beat me to it while I ate my dinner, lol.

 

[Rusty Nail]

Pig

 

[Smtty58]

Why wouldn't this work?

https://www.holley.com/products/fuel_systems/fuel_pumps_regulators_and_filters/regulators/carbureted_regulators/parts/12-887

I read somewhere that can only handle 12 psi input pressure. If that's wrong, then yes, that will work.

 

[bucket]

I read somewhere that can only handle 12 psi input pressure. If that's wrong, then yes, that will work.

I've never heard that before. I know they normally get used with higher pressure pumps and it works fine. Out of curiosity, I looked through the questions that have been asked on Summit about the regulator that I linked. It says this:

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[Smtty58]

Thanks Bucket!

 

[Ricko1966]

You have to take into account the size if your return line it needs to large enough the eventually it cannot bypass any more fuel. If/when it cannot bypass anymore fuel then pressures start to climb. I haven't had any trouble on TBI or other injection with pressures under 45psi. I did have a problem with a 98 chevy vortec. The factory bypass line was too small, it became a restriction and ramped up the fuel pressure.. also if your block has the mounting pad for a fuel pump just no pushrod provision. You can mount a factory pump and use factory lines for clean plumbing up front I'd try using g a factory pump as my bypass keep drilling the restrictor larger until you are bypassing enough fuel.

 

[idahovette]

There ya go!!!!!!!

 

[Grit dog]

TBI pump in the tank and a regulator. Good to go. And a smart relay or pump that has that so that it’s not just key on.