Why The Slant Six Won’t Die In This 1965 Plymouth Valiant

Key things

  • The Chrysler Slant-Six engine, while not a powerhouse, has a dedicated fan base due to its reliability and ease of maintenance.
  • Powered by a Slant-Six, the 1965 Plymouth Valiant is a run-of-the-mill car that still refuses to quit, a testament to the engine’s reliability.
  • The Valiant has some modifications for better performance, such as a “Super Six” twin-barrel intake manifold and carburetor setup.



When we think of the classics racer engines, our minds gravitate towards things like Chrysler Hemi V8 or Ford’s 428 Cobra Jet to name a few. High performance V8 engines were the driving force behind many classic cars that a lot of other engines fall in the path of our rosy imagination.

However, there is actually a good reason for this. Power and performance are sexy. Reliability and economy are not, and the Chrysler Slant-Six engine was never quite like that tire shredding powerhouse. Still, the engine has a devoted fan base, many of whom praise its supreme reliability and ease of tightening. characteristic inline-six sound.

While this engine has found its way into many entry-level Mopars over the years, it is perhaps the best known powering all four generations of the Plymouth Valiant. Jamie from Dead Dodge Garage YouTube channel is an expert on all things Mopar and recently acquired this seriously neglected 1965 Plymouth Valiant 100 with a Slant-Six that struggles a bit but still refuses to kick the bucket.


The Chrysler Slant 6 was the underdog of the Muscle Car era

At the dawn of the muscle car era, Chrysler produced the legendary 6-cylinder engine that showed us what the engine was capable of.

This 1965 Plymouth Valiant was once someone’s pride and joy

1965 Plymouth Valiant Key Details

  • The Plymouth Valiant was introduced in 1960 as Chrysler’s competitor to the Chevrolet Corvair and Ford Falcon in the emerging entry-level compact car market.
  • Chrysler designed the Slant Six engine to replace the aging flat inline six, with durability and economy at the forefront of the design.
  • This ’65 Valiant was cared for long ago, but has now been left to rot for a long time
  • Despite a bit of a struggle, the slant six in this Plymouth confirms its reliable status and continues to run after years of neglect.

While the Plymouth Valiant and its companion straight-six were Chrysler and Plymouth’s entry-level models for the 1960s and 1970s, they still amassed plenty of enthusiasts over the years. Chrysler adopted the 30-degree inclined straight six first promoted the Mercedes 300 SL and built their own Slant-Six to replace the aging flathead six that had been around since 1929.

This Valiant 100 has Chrysler’s smallest 170 cu-in inline six that produces 101 horsepower and 155 lb-ft of torque. While these numbers sound pretty anemic, keep in mind that prior to the early 1970s, strength data was measured differently. Thus, the actual performance would likely be even lower due to differences in gross and net performance measurements.


A junkyard 1971 Plymouth Scamp is begging for a Hemi engine swap

This little-known kid’s muscle car needs a serious rebuild, including a new engine and transmission.

Even in the 1960s, the Valiant was never a tire-shredder, but despite its somewhat underwhelming performance, this 1965 Plymouth was someone’s pride and joy, and it has a few modifications that put a little more pep in its step. The main improvement to this Valiant is the addition of a “Super Six” twin-barrel intake manifold and carburetor settings according to slantsix.org.

The Super Six package was a performance option offered on all lean-six cars from 1977-1980 and included a twin-barrel intake manifold, Carter BBD twin-barrel carburetor, different throttle cables, throttle mounts and return springs, and a Super Six air cleaner—all of which reportedly increased power by 10%, according to enginelabs.com.

Other customizations on this Plymouth Valiant include an aftermarket stereo and subwoofers, and a custom red trunk carpet to match the interior. The car also sits lower than factory settings aftermarket suspension and has an additional transmission cooler.

Years Of Neglect Left A Classic Plymouth In Pretty Rough Shape

While Jamie doesn’t provide much information about the history of this classic Plymouth, it’s clear that this car has been unloved for quite some time. While the car still has all of its original bodywork attached, there is quite a bit of mildew, dirt, and corrosion all over the exterior of this Valiant.

Jamie also says there’s a lot of Bond residue and fiberglass, summarizing the car by calling it “a total rust pile.” This makes all sheet metal, except for the windshield cover, appear to be straight and have only minor surface corrosion.

The interior of the car is a mixed bag, with the dashboard seemingly in decent condition, if not a little dirty. While the Valiant’s basic design means the interior is very simple, all the original gauges, switches and knobs are still there, and it even has the original steering wheel.

The wheel itself has a replaceable cover and is overall nicely shot with plenty of clearance in the post and sprocket. Meanwhile, the headliner is almost completely gone, and what’s left is rapidly degrading.

Slant-Six in this Valiant fights but bursts into flames

1965 Plymouth Valiant 100 Specs


170 cu-in (2.8 liter) naturally aspirated inline six


Front engine, rear wheel drive


3-speed automatic

Power supply

101 horses


155 lb-ft


$10,613 (average)

(figures with permission automotive catalog/classic.com)

Aesthetically, the Slant-Six looks as bad as they come in this Plymouth. There is heavy corrosion on the manifold, valve cover, carburetor, distributor and most of the rubber hoses and wiring.

Jamie then checks the fluids and finds that the little Plymouth has some oil left, but it has absolutely zero coolant. After topping up the coolant, Jamie checks to see if he can start the car and is less than surprised when the engine jumps, if only for a moment.


10 inline six engines with bulletproof reliability

Straight-six engines were the most popular design for six-cylinder classic cars and are still produced by modern automakers such as BMW and Mercedes-Benz.

At first, Jamie was worried that he would have to record ignition points to get the car going. Fortunately, he manages to skip this lengthy and rather unpleasant process and is working on sorting out the BBD carbs, which seems to be the main problem.

Annoyingly for Jamie, the Super Six kit installed on this Valiant came with a later model BBD carburettor, meaning he can’t pre-fill the carburettor with fuel due to a plate blocking the bowl. This carburetor also has significant fuel leakage around the throttle, which is a common problem with BBDs.

While Jamie can start the car, it won’t idle, so the next step is to remove the carburetor. After cleaning all the passages and bowls, as well as installing a new bottom gasket and adjusting the idle bolts, the BBD carb still has no idle fuel. To solve this problem, Jamie completely shuts off the carburetor chokeit vacuums out all the debris that is clogging the passages and the car now idles smoothly.

A 1965 Plymouth Valiant is $10,613



Avg. Business price


1965 Plymouth Valiant

10,613 dollars


(data provided by classic.com and JD Power)

After tightening the alternator belt and de-sticking the gas pedal with rust remover spray, Jamie takes the car for a spin around the Dead Dodge Garage. Surprisingly, the Valiant shifts into gear without a problem, and even the brakes and power steering work. Even the alternator charges, and Jamie celebrates by doing a few drifts of grass and burnouts—a testament to the Slant-Six’s stubborn reliability.


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While many ’60s classics can be expensive for collectors on a budget, these ten are cheap and likely to skyrocket in value soon.

While this example is a long way from being a public hall car, it now runs and drives and is a prime candidate for a restoration project, turning a profit isn’t your goal. Values ​​for 1965 The Plymouth Valiant costs around $10,613, according to classic.com, and the ceiling isn’t exactly high, with top selling prices only reaching $14,200. This Valiant is apparently for sale and probably for a low price too.

Source: YouTube @ Dead Dodge Garage, classic.com, JD Power, automotive catalog, enginelabs.com, slantsix.org