Getting to that time where I need to decide whether I'm going to run a mechanical fuel pump off the engine or put in an electric fuel pump... the motor will probably be pushing a little over 500 horsepower on the street with a Quick Jet SS-760 carburetor
what's the pros and cons?
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Go for the mechanical pump, but use a metered-orifice, 3 nipple fuel filter after the pump hooked to a return line to the tank Also insulate the fuel lines when they pass anywhere near heat, especially when near the motor. 3/8 feed and 1/4" return is more than adequate.
With your mild build, it's the quiet, reliable and inexpensive way to go.
If you do go for an electric pump, be sure to wire it in using relays, a low oil pressure cutoff switch and a bypass switch to allow for priming.
Modern cars no longer use return style systems. They use deadhead systems with a PWM (pulse width modulated) fuel pump controller that is managed by the ECM, which you don't have.
A lot of guys throw a high-volume, in-tank electric pump in their fuel tank and run a traditional bypass style regulator up front. This works well for short duration drag racing type use, but on a street car its not so ideal.
The problem is that the pump is running full blast the whole time. That is the equivalent of having a 240 watt light bulb in your tank. The fuel doesn't take long to absorb the significant heat that is created by it. With a full tank, it is an issue, with a low fuel level, it is concerning.
If you are running EFI, you can modulate the power of the pump without damaging it using PWM, which turns on and off the power to the fuel pump hundreds of times a second to match pump output with the different amounts of fuel required during idle, cruise and wide open throttle.
Without the EFI computer to control the PWM like on a carbureted motor, it is difficult to match pump output to fuel requirements. The only recourse is to run full power to the pump and bypass the unneeded fuel back to the tank. It's inefficient, heats the fuel supply and the pump doesn't last as long.
There are a handful of companies trying to address this issue on carbureted motors right now, but it is technically difficult to do without the engine management computer. They have to attempt to use the relatively low fuel pressure at the regulator. It can be done at higher pressures, but the low pressure makes it difficult to properly manage.
Fuelabs does make a two speed electric pumps that can be triggered by throttle position or the secondary's on a carb. This is how I decided to go on my carb'd set-up using a full return regulator. The pump runs at low speed until triggered by the opening of the secondary's. Then it goes to full power/flow.
The attached file is the instruction sheet to the 2-speed pump I chose. It has some good info applicable to all electric pump based fuel systems.
