# fuel supply help



## rbpwrd240 (Mar 19, 2007)

Ok guys just realy updating and probing for info. My build is on a 65 GTO. It is time to get the fuel tank in and get the engine some gas.

Here is my parts list
1. 140gph fuel pump 70.00
2. Electric fuel sending unit ? (ebay) 45.00
3. Fuel tank coating 40.00

So were using the old gas tank which keeps costs down, but realy its becouse the old tank wasn't in to bad a shape. The electric pump will have a regulator becouse the gto factory fuel pressure is between 5 and 6.5lbs and most of the ones iv seen work at 9 or so, we will figure out the correct pressure for our aplication. One thing im worried about is if the 389 we plan on building later will work with an electric pump, given that it will be a 389 triple carb setup. I dont know if the constant supply of fuel will hurt it.

Last thing, those fancy racing canister setups where they have a small canister always being filled withfuel and then a line running up to the motor where does that become a necesity or is only on huge horsepower aplications where the motor could ask for more fuel then the pump can deliver?

Let me know if you guys have any tips,advice, or input.

Happy building


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## Rukee (Feb 8, 2007)

I have a `65 with Tri-Power and the stock mechanical fuel pump and it all works just fine. If you`re going to be all stock, or close to it, I`d just run what`s supposed to be there. I hate the way the electrical pumps make so much noise. The canister things may be a cool can which cools the fuel before the motor uses it, not so much a reservoir for the fuel. A mechanical pump also feeds fuel constantly anytime the motor is running. Unless your motor is going to consume more fuel then a mechanical pump can deliver (and you can get high volume mechanical pumps) I would not use an electrical pump. Just my 0.02 cents.


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## Tri-Power (Jan 10, 2008)

From my experience ('66 Tri-Power) I would say the stock mech. fuel pump should be plenty if you are planning to stay within the realm of stock.


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## geeteeohguy (Feb 2, 2008)

Both Rukee and Tri Power are absolutely correct. I've seen more fires and flooding due to electric fuel pumps than I care to remember. I ran a '66 for years with a stock pump, and have run my 65 for 26 years with a stock pump, both tripower cars, both with big cams, 4 speeds, etc. Never had a problem. The 389 only needs about 4psi pressure to be happy. It's volume that matters, more than pressure, but the stock mechanical pump is more than up to the job. My opinion is to lose the electrical add on stuff and stay stock and reliable. Good luck.
Jeff


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## VettenGoat (Jun 19, 2007)

Stick with the mechanical pump and save your money for something you really need. My stock fump pump feeds the tri-power without problem. BTW, Have you dropped your tank yet? If not, check the frame sections where the two straps hook in as they are often rotten out and need to have replaces wielded into place.

Mike


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## rbpwrd240 (Mar 19, 2007)

Sorry guys i forgot to mention one huge factor. Currently we are going to run a 455 bored .060 over and with 12.5:1 C.R. lunati bracket master cam.

we plan on running an 850-900cfm carb. I wanted the electric fuel pump for this motor. Est H.P. is around 550whp and 600+lb/ft of torque. Can a mechanical pump handle this high a demand?


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## Rukee (Feb 8, 2007)

I would expect a high volume mechanical fuel pump would handle that.


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## 5hundo (Sep 10, 2007)

This actually relates to something with my 67 Le Mans that I've just had a little fuel supply trouble with. So, if it's not too much trouble, can I piggyback off this thread (to save from starting a new topic)?

Keep in mind that I bought this car in mid-build and a lot of this was not my doing. When they put in the 455, they added an electric pump and a nice fuel rail with a gauge and everything. The gauge never registers a number, so I've assumed that it's broken.

I'm running a 4bbl Holley (750, I think but I haven't looked that close) and an Edelbrock torquer manifold. So, should I just rip all of that electric junk out and revert back to mechanical?

If so, will I need the High Volume Mechanical pump?


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## Rukee (Feb 8, 2007)

^That`s up to you. It`s there and working, you may want to just leave it. If the electric pump is noisy and you want a stock appearance, then I`d change it over. A stock mechanical pump should do the job fine.


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## 5hundo (Sep 10, 2007)

Rukee said:


> ^That`s up to you. It`s there and working, you may want to just leave it. If the electric pump is noisy and you want a stock appearance, then I`d change it over. A stock mechanical pump should do the job fine.


The noise doesn't bother me and the "stock appearance" think is a moot point since it's got an Olds engine...  (for the record, that was not my doing) 

I think I'm going to need a bigger electric pump if I decide to stick with it, though. It seems like the engine is getting enough fuel to idle and even rev up while parked but the minute you try to take it on the road, it won't go very far. I'm thinking I'll change the fuel filter(s), buy a new pump and see if I can't boost the pressure up a bit.

The fuel rail has a gauge on it that never reads anything. I assumed the gauge was broken but perhaps it's just not getting enough pressure to read. Can someone give me a suggestion on what volume electric pump to use on a 455 with a Holley 750?


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## Rukee (Feb 8, 2007)

Most any pump (electric or mechanical) should be able to keep up with a single Holley 750. You could try to pull the fuel hose off the carb and run it into a gal. container and test to make sure your getting a good supply of fuel. If it`s getting good fuel and it still runs like it does, then maybe the carb needs rebuilding. Or better yet, replacing. Personally I hate old holleys, the new edelbrock durashine carbs work great and are easier to tune.


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## 5hundo (Sep 10, 2007)

Rukee said:


> If it`s getting good fuel and it still runs like it does, then maybe the carb needs rebuilding. Or better yet, replacing. Personally I hate old holleys, the new edelbrock durashine carbs work great and are easier to tune.


I've been considering this as well. I've been thinking about an 800cfm Thunder series.

Is that excessive? 

Any reason why I'd be better off with a Performer Series 750, or something else?

(I too, am not a huge Holley fan :agree )


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## Rukee (Feb 8, 2007)

Unless your going to be at the track alot, or going to be street racing, alot, I would opt for the 650cfm carb. The gas millage will be tons better. If it`s not going to be a driver and all your after is top end performance, then by all meens, get the bigger carb.


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