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**RPOZ11** · 02-20-2016, 10:18 PM

Hey all.
Been a few weeks since commenting on my rebuilt engine in the C/20 here.
I got her up to 500 miles on the break-in and was running well.
Still need to adjust those valves across both heads.

But I ran into another issue with this truck that my SWB was doing.
The mechanical fuel pump quit working.
Its an aftermarket new fuel pump thru the O'Reilly chain.
I had to replace the new one installed when I fired it, and now this 2'nd pump has failed.
On my SWB, I went thru 6 of these things.
Rather maddening.
Gas?
Manufacturer overlook on the diaphrams?
I don't know but on my SWB, I ended up installing a Holley Red Electric pump.

I am doing the same for this C/20.

What I am going to reach out for here is anyone's experience on fixing this issue.

My plan :
Holley Red pump
(now mounted on the outside of the frame just forward of the tank)
Holley Aluminum Fuel Filter, 100 Micron (before the pump)
Holley Fuel Regulator
2 metal Fram type inline filters, 1 before and after the regulator
Fuel pressure gauge
Holley 12-753 wiring harness and relay with inline fuse

Ive been digging around trying to educate myself on the vent lines.
I'm reading that most suggest making that work.
By keeping the fuel continuously moving from tank to carb back to tank.
(I need to see what Fuel Tank Vent exists)

I came up with the idea to install an inline fuel fitting after the regulator and before the hard fuel line going into the Quadrajet; closest to the QJ as I have available.
I'm going to try using a 1/8NPT X 1/4 vent fitting and reroute the fuel back to the tank thru the factory return line.
I have also read that I should consider that the ID of the return side back to the tank should be no bigger than .060.
Not to lose fuel pressure and to allow fuel movement. With my 1/4 vent side it will match the GM line size, I think.

What I am hoping for to work here is that this vent allows fuel to exit and continue fuel movement in order to prevent vapor lock and keeping the fuel cooler. I have not seen any info around addressing this in our trucks for these years.
What I don't know is how this will affect the rest of the factory tank system as installed.

This is what I am installing Sunday.

Anyone care to suggest anything into what I am attempting to accomplish here?

02-20-2016, 10:18 PM	#19
RPOZ11 72 BB C30 Super LongHorn Join Date: Nov 2002 Location: Chavez Ravine Posts: 1,606	Re: 1973 C20 Cheyenne Super 454 Hey all. Been a few weeks since commenting on my rebuilt engine in the C/20 here. I got her up to 500 miles on the break-in and was running well. Still need to adjust those valves across both heads. But I ran into another issue with this truck that my SWB was doing. The mechanical fuel pump quit working. Its an aftermarket new fuel pump thru the O'Reilly chain. I had to replace the new one installed when I fired it, and now this 2'nd pump has failed. On my SWB, I went thru 6 of these things. Rather maddening. Gas? Manufacturer overlook on the diaphrams? I don't know but on my SWB, I ended up installing a Holley Red Electric pump. I am doing the same for this C/20. What I am going to reach out for here is anyone's experience on fixing this issue. My plan : Holley Red pump (now mounted on the outside of the frame just forward of the tank) Holley Aluminum Fuel Filter, 100 Micron (before the pump) Holley Fuel Regulator 2 metal Fram type inline filters, 1 before and after the regulator Fuel pressure gauge Holley 12-753 wiring harness and relay with inline fuse Ive been digging around trying to educate myself on the vent lines. I'm reading that most suggest making that work. By keeping the fuel continuously moving from tank to carb back to tank. (I need to see what Fuel Tank Vent exists) I came up with the idea to install an inline fuel fitting after the regulator and before the hard fuel line going into the Quadrajet; closest to the QJ as I have available. I'm going to try using a 1/8NPT X 1/4 vent fitting and reroute the fuel back to the tank thru the factory return line. I have also read that I should consider that the ID of the return side back to the tank should be no bigger than .060. Not to lose fuel pressure and to allow fuel movement. With my 1/4 vent side it will match the GM line size, I think. What I am hoping for to work here is that this vent allows fuel to exit and continue fuel movement in order to prevent vapor lock and keeping the fuel cooler. I have not seen any info around addressing this in our trucks for these years. What I don't know is how this will affect the rest of the factory tank system as installed. This is what I am installing Sunday. Anyone care to suggest anything into what I am attempting to accomplish here? __________________ 72 BB C/30 Longhorn Super HO72 No-Spin, #'s matching, Tilt, Tach, AC, AM/FM HO72 build : http://67-72chevytrucks.com/vboard/s...d.php?t=714492 2017 SS Last edited by RPOZ11; 02-20-2016 at 10:24 PM.