Skip to main content
  1. Leisure
  2. Autos & Motorcycles
  3. Car & Truck Enthusiasts

The discontinuation of the 440 Six Pack

See also

Was chatting with several friends about the 440 Six Pack that was discontinued for 1972. If you’re not into Mopars, you may not be aware that this engine was cancelled within days of the introduction of the 1972 model year, yet several cars managed to be produced while the plug was being pulled. If Chrysler went through the trouble to produce this motor and have it certified by the EPA, why was it cancelled?

More Photos

Certainly 1972 was a tough year for Detroit, as EPA-mandated changes meant motors had lowered compression and ran on no lead/low-lead fuel. General Motors actually did this across the board the year before while Ford and Chrysler gave the world one more model year of high-compression, high-performance motors (two notable exceptions: Ford released the low-compression Q-code 351, sometimes known as the 351 Cobra Jet, mid-year 1971; and Chrysler downgraded the 383 from 335 hp to 300).

When the 1972 model year came around, Chrysler revamped its performance lineup with the new values imposed by the government. The 426 Hemi was gone, leaving the the 440 as top dog; however, the 440 (and 400, which was an outgrowth of the 383) was shed from the E-body Barracuda and Challenger lineup, making the small-block 340 the top engine. The mid-size B-body Satellite and Charger could get the 440, both in 4-barrel and 6-barrel forms. The latter was rated at 390 gross hp in 1969-70 and 385 in 1971 (some literature also shows 330 net horsepower in anticipation of the new horsepower ratings). For 1972, Chrysler continued the availability of the Six Pack motor, but only for automatic-equipped cars, and only for 49 states (sorry, California!). The Hamtramck Historical website has a Dodge dealer document that shows the availability of the 440 Six Pack, but it doesn’t mention horsepower. It also states the Six Pack had 10.3 to 1 compression - the same as 1971; in comparison, its 440 4-barrel sibling had 8.2 to 1. Another document, this one from Plymouth, shows the motor rated at 330 net horsepower, which you can see is the same as its rating for 1971.

So was it possible to produce a motor for the American market that basically went unchanged from the year before? It would require more investigative research on the EPA's rules for 1972, but we do know that the Six Pack was cancelled very early into the model year. Only about 3 Charger Rallyes and Road Runner/GTXs are known at this moment:

  • Charger Rallye WH23V2G100006 - FE5 Red, scheduled Sunday, 8/01, pilot car built months before & shouldn't have been sold to the public.
  • Charger Rallye WH23V2G100075 - FY1 Top Banana, scheduled Monday, 8/02, promo car.
  • Road Runner/GTX RM23V2G105346 - FE5 Red, scheduled Saturday, 8/07, Air Grabber hood, sunroof.

A motor with high compression and requiring premium fuel was completely different from every other engine being produced in America at the time. Could it have been an EPA issue? A friend offers a different opinion:

  • The data book, order sheets and pretty much all pre model year info shows the 6bbl. would be in production.
  • Emission standards are known well in advance for the upcoming model year. If Chrysler knew the engine would not meet EPA standards, then I think they would not have even included the info in the literature and planned production accordingly.
  • Known cars show the option was only produced for about a week and in very small numbers.
  • If emission standards would have been a problem, I doubt Chrysler would have expended the effort to even produce the cars they did knowing they would be “illegal.” Production of the 6bbl. would not have offset the fines/regulatory problems they would have encountered by producing it.
  • The data book update [see slideshow for update] indicates changes are due to the wage and price freeze. Regrettably, there is no date to the addendum. External, quickly implemented regulatory changes would bring a quick halt to production. Other significant changes were implemented for the ’72 model year. It was not just the 6bbl. that was axed. The 6bbl. just happened to be one of the options caught up in the changes.
  • If you look through the entire update, you can see there were numerous deletions and many would lead to retail price cost cutting (one of the items mentioned is even the deletion of the Pentastar from the RH side of vehicles, hardly an item of significant cost but all pennies add up to dollars.
  • In my mind, and until other evidence surfaces, the addendum spells out more clearly as to why the 6bbl. was dropped than any other explanation. Quickly implemented economic policies caused Chrysler to quickly pull the 6bbl. and other options.

Not convinced, I then introduced a well-known story of a low-compression performance V-8 and the issues the EPA had with it: Pontiac’s 1973 Super Duty 455. The Cliff Notes version is that the motor passed certification but the EPA required re-certification when they realized Pontiac was exploiting a loophole. Could the 1972 440 Six Pack have a similar issue but Chrysler decided to throw in the towel?

Back to my friend: Emission standards are well established ahead of time. If there was a concern about emissions, then I think you would have seen caution and a delay in production like your example; not production at the first of the year hoping they would meet standards. The problems not meeting the standard would not have outweighed the benefits of producing the car. The 6bbl. would have had to have been projected to be a low production vehicle and more of a way to hang on to a performance image than anything else. Cutting the option would have not been that big of a deal from an economic standpoint.

The evidence I’ve seen points to the 6bbl. being caught up in the economic factors across the whole line. I’ve not seen anything that singles out the 6bbl. specifically.

But I still wasn’t convinced - why spend all this money getting a motor certified, only to discontinue it? - so I emailed pal Dave Hakim, former Mopar Performance marketing guy and currently proprietor of HP2 Communications. Would he know someone who was an engineer at Chrysler? For Hemi fans, they have Tom Hoover, but who’s the Six Pack maven? Dave said he asked this question to Chrysler product planners years ago:

  • Engineering Issues: The 1972 emissions standards came in stricter than originally anticipated, therefore the Six Pack would require severe detuning (carb jetting and timing) to meet these new standards. Product planning and engineering decided it wouldn’t be a good performer with the 8.2:1 compression ratio on the ’72 440 engines.
  • Plant Complexities: By discontinuing the Six Pack option, all 440 engines coming off the line at Trenton Engine (MI) could be built with the single Holley 4160 carb, saving money. Remember, Chrysler had a bad year in 1971 and began losing money, so any means to operate more efficiently for the ’72 mode year and beyond was encouraged by senior management. For example, prior to ’72, Chrysler engines came in orange (for the HP models) and blue (non-HP engines). By ’72, ALL engines, regardless if it was a 225 Slant Six or a 440, was painted corporate blue. Again, a cost cutting move.
  • Sales and Marketing Considerations: Sales numbers of the 440 Six Pack option in 1971 dropped significantly due to many issues - cost and the ever-lurking high insurance surcharges for big-inch, multi-carb engines drove consumers into 340 or 383-powered muscle cars. Remember, Chrysler expanded the availability of the 340 for the ’71 Road Runner and Super Bee.

So where does that leave us? No concrete answers, but it looks like a bit of cost-cutting, a bit of emissions issues, and likely some answers that we have yet to discover.

Do you like cars? Check out the other articles I've written, and feel free to email me with stories about yours or with something you'd like to see.



  • Corned beef
    Find out how to prepare a classic corned beef recipe in a slow cooker
    Slow Cooker Tips
  • Left handed eating
    Find out why you should never eat with your left hand
    Wives Tale
  • Subway message
    Subway customer finds 'Big Mama' written on her order
    Subway Message
  • Deviled eggs
    This is the only deviled egg recipe you’ll need this Easter
    Delicious Eggs
  • Natural solutions
    Natural beauty: All natural solutions to life's little beauty headaches
    Natural Solutions
  • Chocolate souffle
    Love chocolate? Get tips on making the perfect chocolate souffle every time
    Recipe 101

User login

Log in
Sign in with your email and password. Or reset your password.
Write for us
Interested in becoming an Examiner and sharing your experience and passion? We're always looking for quality writers. Find out more about and apply today!