Fuel Pump Options

[fmansfield444]

Alright guys, I've got a question for my motor build. If you don't know, I am building up a carbed roller block 302 to put in my 85 CV after the car went up in flames and scorched my SEFI wiring. I'm looking to build a car that is not a daily driver, but something I can drive on the street and also take to the strip. So far I have gt40P heads, and am planning on mild performance. Anyway, I cant quite decide on how I'm going to pump my fuel. I see that I have 3 options:

1. I could keep my cars in tank electric fuel pump and get a fuel pressure regulator that decreases the fuel pressure to allow for a carb.

2. I can get an electric fuel pump for a carb

3. Or, I can use a mechanical fuel pump for the carb.

I am looking for something that is cost and labor effective but at the same time will work great and is reliable. I like the simplicity of an oldschool mechanical pump, and I already have one plus the timing cover for one. But just wanted to see what you guys think.

[fmansfield444]

Bump

[Tiggie]

Some of the CFI (not the majority) used a high pressure in-tank pump in addition to a low pressure pump mounted somewhere else (maybe along the fuel line on the frame rail). I've never owned a CFI car, so I can't say for sure about it's location. Those that do have it can run it only after bypassing the high pressure pump.

As far as other options, I like it simple. I would use a mechanical pump with the older model timing cover.

[packman]

I've thought about this, but never inquired. Is there a regulator that can knock the SEFI in-tank fuel pressure down to 7-9psi? Probably just easier to change to the CFI system like Tiggie said above.


Packman

[packman]

I've thought about this, but never inquired. Is there a regulator that can knock the SEFI in-tank fuel pressure down to 7-9psi? Probably just easier to change to the CFI system like Tiggie said above.


Packman

[sly]

yes, there is a regulator that can bump that pressure down, but it's rather spendy. the dual pump systems used a low pressure pump in tank and high pressure pump next to the filter IIRC.

[1987cp]

I've thought about this, but never inquired. Is there a regulator that can knock the SEFI in-tank fuel pressure down to 7-9psi? Probably just easier to change to the CFI system like Tiggie said above.


Packman

I think Bowman85merc did that with just a T fitting, no regulator at all, and reported satisfactory results with his carb conversion. I don't remember whether his car came with a high pressure or low pressure in-tank pump, though. Logically, a suitable bypass regulator would be a better option.

If you get a mechanical pump, get a stock one for a '79 LTD, as they're 40gph versus 30 for the later bypass style, or if going aftermarket consider an Edelbrock since they come in ~5psi output ratings. I went cheaper with a Summit pump and had to complicate things with a regulator. I also think the inlet and outlet for the Edelbrock pumps are independently clockable (important since pumps for older Mustangs have the inlet and outlet reversed compared to a Box LTD pump).

[gadget73]

You're much better off replacing the high pressure pump with one designed for a carb application. Whether its electric or mechanical is your option but the regulator stuff is a lot more expensive and complex than a simple low pressure pump that is designed to do what you want already.

[1987cp]

^ Agreed, my regulator install was quite annoying, added a small but nasty "hidden" expense, and was constantly messing with my brain afterward from watching the fluid-filled gauge fluctuate.

[Tiggie]

the dual pump systems used a low pressure pump in tank and high pressure pump next to the filter IIRC.

Thanks for clearing that up. Pesky CFI oddness. My box tech skills are rusty!

[fmansfield444]

I didn't see any pump along the fuel line near the filter but I just looked without jacking it up. So it looks like I'm going with a mechanical pump. Probably just a cheapy for now as I'm just trying to get the car running. For the fuel lines, rubber fuel hose should suffice right? Or should I go braided? The rubber held up under SEFI pressure so carb pressure should be no problem

[sly]

the high pressure pump would be mounted ABOVE the filter.

[fmansfield444]

Well my car did not have 2 pumps.

I went ahead with a small electric pump because I thought that after I go through the trouble to remove the timing cover and all that bs and buy gaskets, It would be less work and just as much money to buy an electric and mount it on the frame.

So I have it all hooked up to my carb and it ran well. Wasn't too hard to do and isn't too loud at all.

Hardest part was probably removing the tank.

Thanks guys.

[sly]

yeah... dropping the tank isn't that horrible... putting it back can be a bitch though.