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Discussion Starter · #1 ·
385 hp, 351w carb motor, IRS pin drive, TKO 600, 355 gears, fuel cell.
Electric or mechanical fuel pump??
Why??

Dont get me wrong, I know why it will need a fuel pump.

Robert
 

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1,506 Posts
I'm going mechanical as it is what comes with my 351 from Engine Factory. I had some concerns about it at first but after talking to several people who have the same setup and have had no problems I decided to stick with it. I also like the simplicity as far as fuel system etc.
 

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Clyde, I am going electric. I have a donor engine (former EFI) converted to carb and with a donor tank. I had to switch to low preasure system so decided to go electric fuel pump. I rebuilt the engine myself, first time, so if I have a problem I will be able to find a fuel problem easily! Also, I will install a fuel pump kill switch for security.

Prost,
Rich
 

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Clyde,
I went mechanical for the same reason as Michael ... simplicity of the fuel lines. Here are some pros and cons:
Mechanical is simple ... one line from the tank, no wiring, no cut-off switch, no pressure regulator up front to bring the pressure down the to 6 or 7 psi the carb needs. The con is that you are prone to vapor lock, especially if you route your fuel line near a header. The first start requires a prime. You don't want to crank the engine until the mechanical pump has a chance to fill the floats.
Electrical is, well, more regulated. You bring in high pressure to a regulator and bleed off the pressure to a return line. Keeps the fuel cool. You are pushing the fuel to the carb instead of pulling, so no vapor lock. The pump turns on before you start cranking. The floats always have gas, no priming. The con is that you have more parts, the return line, the regulator, the cut-off switch and the pump (in the tank or in-line near the tank) and then there's the whine of the pump when you turn on the ignition.

Both work well, it's really a matter of preference.

Pete
 

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FFCobra Craftsman
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1,659 Posts
An under 450HP small block with 3/8 lines should be ok with a performance mech pump , about 35-45 GPH at rated pressure (ignore Free Flow advertised ratings) , I like Carters and there are several that will work . A nice high end mechanical pump would be a CV products NASCAR pump , there is a good selection for small block Fords and Chevys
If you need it you can add an electric later on to feed the mechnical with or without a check valve , I did and can shut the electric off and run off the mechnical only.
 

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FFCobra Fanatic
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12,975 Posts
I went mechanical pump on mine. Only ran one 3/8" line intead of two lines. Ever need to change a fuel pump it's right up front and inexpensive to buy. Since the engine was already apart it was no more effort to install the excentric and timing cover. Just felt it a more simple install then going electric.
 

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883 Posts
I used a Holley Red fuel pump on a 4bbl mustang once, It worked well, great performance but the noise was so bad I had to take it off. Might not be so bad in a Cobra but it can be heard over a 300hp 5.0L through dual flowmaster 40s with the top down at 75mph.

I'd use the mechanical pump if I had the choice.
 

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I went carb and mounted the holley red model near the tank, I wish I could run mech. the electric is noisy, maybe I can mount it on rubber.
chas
 
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