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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Great post as always, Mike!

From where do you source these pumps, Mike? Ian is about to start the restoration of the 66 Mustang I gave him years ago and he might be interested in those pumps that are known to work.

I used to pick them up at the local parts store (NAPA I think). The last few years I've been doing Amazon. Here's a link


https://www.amazon.com/Universal-Ele...zcF9hdGY&psc=1


One of the few things the price has come down on over the years ( I suspect I know where there made now) Don't know about these till we actually get the car going.The last one's I used was a few years ago and they did fine.


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Thanks Mike

Good Stuff Mike. I did something similar in my coupe. I used a 3 port regulator to "dump" excess pressure/fuel back to the tank. A holley vane pump drawing from the tank. It all worked very well. EXCEPT - I hated the noisy pump! I could hear it at every stop light / sign and it was only a 6 pound system. I removed it and went to a stock mechanical when I disassembled the front end for some cleaning and installing the Shelby intake and valve covers.

I know what you mean about the Holley pumps being noisy, had a couple of customers who used them. On the pumps I use I used to stuff rubber grommets in the mounting holes, but found that really didn't make any difference. Mounting location does seem to make a difference, mounting to a frame rail works but mounding to an inner fender or or trunk floor gets a little noisier.

Normally is possible I like a mechanical pump best, and just add the electric pump to fill the carb on startup.


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Originally Posted by Mike P

On the pumps I use I used to stuff rubber grommets in the mounting holes, but found that really didn't make any difference. Mounting location does seem to make a difference, mounting to a frame rail works but mounding to an inner fender or or trunk floor gets a little noisier.

Normally is possible I like a mechanical pump best, and just add the electric pump to fill the carb on startup. .

I tried rubber isolators between the frame and pump, but it made little difference. I don't mind spinning the motor over to refill the carb(s), it allows time to build oil pressure, jmho..

We managed to get a couple of other small things taken care of.

One was blacking out the front of the core support. When the sun hit the front of the car just right that green paint on the core support really stood out and just didn’t look right to me.……much better now.

CS BO by M Patterson, on Flickr


The other little project was converting to cable operated hood latch operated from inside the car (yes, there are assholes out there who think it’s perfectly OK to open the hood of a strangers car ……I’ve run into a couple of them). I’m not sure if the cable operated latches were optional on the 68 Valiants, but my latch is good and it was just easier to convert it and add a new cable from Amazon than it would be to dig up on original latch and cable….. if available…..and most of the used factory cables I’ve seen have cracked handles anyway.

Unbolting and removing the factory opener handle was straight forward. The mods to the latch itself were also pretty simple. A split bolt to hold the cable end was installed and then a small bracket to retain the end of the cable housing was fabricated and welded to the latch assembly.

Latch Cable by M Patterson, on Flickr


And mount the handle to the dash.

hood release by M Patterson, on Flickr



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Looks Factory!!

We got what should be about the last of the work we needed to do to do to the body before the engine and transmission goes in, reinforcing the crossmember brace in the trans tunnel.

The brace that we needed is 2” across, so I started with a ¼” X 2” piece of flat stock, To get the shape roughed out I clamped the piece we cut out in the vice and then clamped the piece of flat stock to that. With a lot of heat and hammering we finally had a piece we could work with.

tunnel brace by M Patterson, on Flickr

After several trips under the car for final tweaking it was welded in and then Cade got to spend some quality time with the grinder cleaning up the welds and shooting some paint on it.

tunnel brace (2) by M Patterson, on Flickr


It's a little hard to get a good picture of it, in person it actually looks pretty good. Between that piece ¼” flat stock stock and the welded in subframe connectors I don’t think there will be any issues.

The rest of the day was spent getting the engine off the run stand and removing the bellhousing, flywheel and spacer plate.

I got it mounted on the engine cart this morning and next will be getting the adapter and transmission mounted. After that will be sorting out throttle and kickdown brackets and the kickdown cable. Then I guess we’ll see it all fits LOL.


Eng 46RH by M Patterson, on Fl.


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Break out the shoe horn...........

“…..Break out the shoe horn.......”

Not quite ready for that Bob.

The engine and transmission will be going in as a unit so next up was bolting the transmission on. I’m using Hot Heads early hemi to small block 904/727/500/518 transmission adapter. This is the same adapter I used on the 37 Dodge PU with the 331 Hemi.

The instructions that come with the adapter are pretty minimal, so some figuring out is required.

Trans adapter inst by M Patterson, on Flickr

Doing the installation can be a bit of a pain, but it’s one of those jobs you should only have to do once.

Rather than cover the specifics involved in installing the adapter, if you’re interested in the details, I did a write-up in the engine forum on this site where I covered the installation of the same adapter on the 37 Dodge:

General Hemi Info part 3



I spent some time sorting out the new throttle, kickdown and cruise control brackets and cables while the engine and transmission was still out.

Throt KD Cruise by M Patterson, on Flickr


Kickdown by M Patterson, on Flickr


With that taken care of the engine and transmission were finally installed.


NOW IT"S TIME FOR THE SHOEHORN LOL


Engine install by M Patterson, on Flickr


Right off it was evident that the high mount alternator and compressor brackets were a non-starter. I was kind of expecting this problem so it was no surprise.


ZZ Upper brackets by M Patterson, on Flickr


I had built all the brackets that were on the HEMI, so other than some time I really don’t have any money tied up in them. At some point I’ll put them up for sale along with the PS pump brackets and make a few bucks on them. Fortunately, Hot Heads sells low mount brackets that should alleviate the problem. Theare also designed for use with a Sanden 508 compressor and GM style 10 SI alternator which is what I was running and will locates the components on the sides I want.


ZZ Low brackets by M Patterson, on Flickr


It also looks like we have an issue with oil filter/torsion bar interference, but all that will take is a different oil filter adapter.

Still a long to do list, but it a good feeling seeing the engine and transmission in its new home.


Eng inst by M Patterson, on Flickr



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We’ve been getting the to do list whittled down a bit.

The oil filter adapter came in and was installed. I’ve used this style before and I’m not necessarily a fan but it does cure the filter interference problem. The upside down position of the filter makes for messy oil changes, but my biggest complaint is when the car sits for several day the oil will eventually drain back so when it’s started the filter must refill before the rest of the oil system is pressurized.


zz filter adapter by M Patterson, on Flickr


zz filter adapter 2 by M Patterson, on Flickr


I also got the low mount AC and alternator brackets and belts sorted out and installed. I would have liked to have run both belts over the water pump pulley but that put the AC belt too close to the lower radiator hose so I used a shorter belt that just runs from the crank pulley to the compressor.


Low Brackets by M Patterson, on Flickr


The hood from the parts car was mated to the car for the first time. After some adjustments it actually fits pretty well and without air cleaners the hood actually shuts. With the air cleaner it will definitely will need a scoop for clearance.


Hood by M Patterson, on Flickr


We’ve got the initial hole cut in the hood and I’m currently working on the air cleaner base.

Air Cleaner hole 1 by M Patterson, on Flickr


A lot of the “hood scoops” I looked at were just a little short for the air cleaner I plan on using. I finally settled on a steel Goodmark cowl induction scoop (2 ½” tall). The “scoop” as delivered is actually longer than the Valiants' hood. I’ve trimmed it a bit so I can get it placed then I’ll do the final trim.

Cowl scoop by M Patterson, on Flickr


The rear of the scoop will be open (with a stainless mesh) and will sit far enough forward that there shouldn’t be any forced air, actually it will likely be in a low pressure area. In effect it should act like the Thunderbolt teardrop scoops and help evacuate hot under hood air.

The current plans for attachment is to flange the opening in the hood so the flange on the scoop sits down in it and be fairly close to level with the hood. I’m not comfortable being able to do a perimeter weld around the scoop with out warping the hood. The plan right now is to use a spot welder and spot weld the scoop to the hood. That’s the plan anyway.


We’ve also been working on the exhaust system. Before anybody asks why I don’t just take it to a muffler shop, I would IF there was one locally that consistently did good work. I’ve been building my own for the last 10-15 years, right after I had the 3rd one come back that had to be redone due to interference issues.

I’m running 2 ½” exhaust, The tailpipes are flow masters and due to the coil overs and slight relocation of the gas tank they seemed work best (after some modifications) coming out at the rear corners instead straight out the back. The front hanger for the ladder bars make getting mufflers in a bit tight but we’re making headway on that. So anyway that’s where we are right now.




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Awesome. Thanks fer sharin.