Thread: 1968 Plymouth Valiant 1st Gen HEMI

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When the fuel tank was installed a while back, we went ahead and started getting the fuel lines installed. When I got the car, the fuel lines were the flexible braided type and run down on the drivers’ side. For this build it actually works better to have the lines coming down the passenger side, so a new 3/8” steel fuel line was run. Rather than re-invent the wheel the 5/16 fuel line was removed from the parts car, cleaned up, checked and installed on the Valiant to use as a return line.


return line by M Patterson, on Flickr


We decided to run the lines up the back of the engine so we terminated the them just forward of the firewall.

fuel lines by M Patterson, on Flickr


The HEMI has no provision for a mechanical fuel pump, so I picked up a couple of universal electric pumps. I know that some will question my choice on these particular pumps. I was quite leery myself when I bought my first one over 35 years ago (at that point I had tried a few different pumps that hadn’t worked out for various reasons and was at the point where I was willing to try anything).

fuel pump by M Patterson, on Flickr


Surprisingly they actually work quite well. I’ve run them as the sole fuel pump on several engines over the years and have not run into any fuel starvation issues, (keep in mind the engines have been street motors under 375 C.I.)

The pumps are available in 4-6 PSI and 4.5-7 PSI. I normally use the 4-6 PSI version and the only modification is to upgrade the included 1/8 NPT X 5/16 barb fitting that come with them to 1/8 NPT X 3/8 barb.

I also have these installed on all of my carbureted cars even the ones where the primary fuel pump is an engine driven mechanical pump. For those vehicles they're wired to an on/off toggle switch and used to fill the fuel bowl after the car/truck has sat for several days (saves a lot of wear and tear on the starter motor). The design of the pump allows fuel to be sucked through when the pump is in the off position.


These pumps have also proven to be pretty reliable, over the last 35 years or so I have only had a total of 4 go bad (about the same failure rate I’ve had with mechanical pumps driven similar mileage).


When I built the car that I had the vapor lock problems with, I actually ended plumbing 2 pumps in series with each pump being wired to one leg of an on/off/on switch (as mentioned I was pretty leery about the first one I bought and changing one out on the side of the road is not pleasant). As the design of the pumps allows the rear pump to have gas sucked thru it when it’s off and the front pump will allow fuel to be pushed thru it when it’s off, it does not cause an issue with 2 pumps plumbed in series in the fuel line. That system worked system worked well so I left the “extra” pump in the system. After about five years of trouble-free operation one of the pumps did go out. It was really nice to reach under the dash and simply throw the switch to the other pump, finish my trip and then replace the bad pump at my convivence. Because of that experience I started installing 2 pumps on all my vehicles that rely solely on electric fuel pumps. Because of the 3 position switch (on/off/on) it also makes a good anti-theft device. In the off position the car will still start, but will only run as far as the fuel bowls will allow (about a block).

Fuel pumps by M Patterson, on Flickr


We still have a bit of work to do like connecting the electrical and relocating the return line a little higher but it’s pretty close to finished.


I normally make up the fuel lines so the pumps are in a “low” spot in the fuel system which causes the fuel to stay in the pumps when the engine is shut down (instead of draining away from the pumps). That way the pumps don’t lose their prime and have an easier job pulling fuel from the tank on start-up.


These are a “clicker” type pump and when they are dry they are pretty loud, however when they’re actually pumping fuel the noise is hardly noticeable (Personally I can’t hear them over the exhaust when the engine is running……but I’m old LOL). I normally switch the pumps over every few months just because.

As this has worked very well for me in the past I have no reason to believe it will be any different in the Valiant.



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