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Chrysler Poly Engine Production Numbers


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Good Evening All,


I am new to this Forum but have read several topics and am very appreciative for the interaction of its' membership. Knowledge is a powerful too and should be shared.


I have a '65 Plymouth Satellite Convertible in my small collection and am ready to start my restoration. Unfortunately I have run into a brick wall when it comes to the availability of performance parts for the Poly engines. Being the owner of a small Manufacturing Engineering company, I am investigation producing my own line of aftermarket performance parts for these "unappreciated" engines. If everyone only knew what a forgotten Jem they are. 


So for the purpose of this thread, I have been searching for production data of the 1954 to 1967 "A Family" Poly engines. I would like to know what the production quantities were for the 277, 301, 313, 318, and 326 Polys. If anyone has this information they could share with me it would be greatly appreciated.


I am also in search of Poly parts to either borrow or purchase for reverse engineering purposes. 


Thanks all you fellow car lovers. Hope to see you in Carlisle, that is after we can travel again.


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Best V8 of it's day, hands down. I have no idea how many were made. It was extremely common in Plymouth and Dodge B and C bodies in 1965 and 1966. Runs of performance parts in the past have all been small. Good luck with your project.

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That first link is a whole different engine.


I usually refer to the engine the OP asked about by the old colloquialism "Wideblock". Although it is just slang, it is the only term I am aware of that refers to ONLY that engine series (277-301-313-318-326). Poly or Polyspherical could be either the Wideblock or the engine(s) in the first link.


In retrospect, it appears "A-Engine" is the correct term for the Wideblock (and only the Wideblock). Allpar has it that way, and have even interviewed engineers, so they are undoubtedly right. Chrysler was never clear about that, and common usage of "A Engine" back in the day referred to every V8 design before the B/RB engines (with the distributor and oil pump in the rear), all the way back to and including the first Chrysler Hemi. They all share some common features and even a part or two will interchange. Apparently that's wrong, but 60 plus years of incorrect usage of "A Engine" will not be undone overnight.


Threads about Polyspherical Chrysler engines almost always wind up with people discussing both engine types and not realizing it.


So to be clear, a Wideblock (or A-Engine if you must), has:


1) Polyspherical heads, canted valves, one rocker shaft per side.


2) A block that has the same bore spacing as all "LA" engines and the "Magnum" engines of the 90s. Sitting on the bench next to an "LA" block, it would be difficult for a novice to distinguish the two. An LA318 or LA340 crankshaft would drop right in.


3) A timing cover, water pump, fuel pump, and harmonic balancer setup that looks almost the same as an "LA" engine and will bolt up.


4) An Intake manifold that includes the water crossover, and closes up the top of the engine, similar to an "LA" engine or a Small block Chevy. (The other type of Polyspherical engines have a pan up top like B/RB engines, early Chrysler Hemis, GM Kettering engines, and Studebakers.)


Item 4 is a super easy way to tell which type you are looking at.


The Wideblock was the only engine ever introduced by Plymouth Division that was exclusive to them. When Plymouth got it's first V8 in 1955 however, it was not the Wideblock. It was the other type of Polyspherical engine, identical to a Dodge engine, except with smaller displacement. In 1956 the Wideblock came along for Plymouth and only Plymouth, but the Dodge-based polyspherical engine continued alongside it. If you open the hood of a 1956 Plymouth, you might see either a Plymouth Wideblock, or the Dodge-based Polyspherical engine.


The Wideblock remained exclusive to Plymouth through 1957 and 1958, while other Chrysler divisions continued to use the other design when a Polyspherical engine was called for. Dual four barrels were optional on the Wideblock 318 in 1957 and 1958 only. Carter WCFB on the 1957s and Carter AFB on the 1958s.


In 1958 the completely unrelated B/RB engines were introduced for all divisions, and a 350ci version was added to Plymouth's option list.


For 1959, the other Polyspherical design engines were all discontinued, leaving Plymouth's Wideblock as Chrysler's only Polyspherical engine.


The 1959 Dodge got a 326ci WIdeblock to replace the discontinued Dodge 325ci Polyspherical engine on the option list. That ended Plymouth's exclusivity on the design. It was the largest displacement Wideblock ever made, but was really nothing that special compared to the others. It was just a Wideblock 318 with an .040 overbore and Hydraulic lifters if I remember correctly. As far as I know the 1959 Dodge 326 is the only Wideblock with hydraulic lifters.


From 1960 on, both Plymouth and Dodge had identical Wideblock 318s on the option list. It was the only displacement still made in the US (but not Canada, more on that in a minute).


For 1962, the new 727 Torqueflite aluminum-cased automatic transmissions replaced the old cast iron Torqueflite. The crank flanges on Chrysler's engines changed. 1962 up Wideblocks will bolt to all the same transmissions the "LA" engines will.


In 1964 the first "LA" engines were introduced, 273ci for use in Valiants and Darts. The block design is nearly identical to the Wideblock, but the head and intake manifold design is completely different.


I don't recall when the single 4 barrel option disappeared, but it was gone for sure by 1965.


1966 318 two barrels were the last Wideblocks in US model cars. 1967 US-made 318s are "LA" engines.


In Canada there was a 313ci Wideblock. I believe this was because when they started making Wideblocks in Canada, they used a bore size from one of the other-type polyspherical engines instead of 3.91. Thus, 313s are unique to Canada and cars made in Canada for export. A year or two before production ended, Canadian Wideblock engines became 318ci like the US models. The Wideblock 318 was used in Canada through 1967, a year longer than in the US.


It is hard to say when production really shut down. They probably kept the line running for a little while to make warranty engines and other replacements. Bristol in the UK was building new cars with Wideblock 318s as late as 1969, but it is unclear if they were getting them from Chrysler or just had a bunch stashed in a warehouse somewhere.


Confused yet? :D



Edited by Bloo (see edit history)
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The Polysphere engine you have is an excellent one, much under rated, and was made in the millions between 1956 and 1966.

First to clarify things. There were different Polysphere V8s that were quite different and parts not interchangeable. Chrysler's V8 program began with the Firepower hemi in 1951 with DeSoto and Dodge versions added in 1952 and 53.

The first Polysphere was a Chrysler hemi block with Polysphere heads made for the Chrysler Windsor in 1954. Everything was the same between the 2 engines except the heads and pistons. The heads were modified to have 1 rocker arm shaft instead of 2, the exhaust valves relocated to suit, the intake basically unchanged, and the pistons had different valve notches for clearance.

There were also Poly versions of the DeSoto and Dodge engine, lower cost lighter weight simplified versions of the hemi for the cheaper models.

Plymouth's first V8 in 1955 was a 270 cu in poly borrowed from Dodge. Quickly replaced by the Plymouth A engine poly in 1956. This was the only Polysphere V8 that did not have a hemi counterpart. It was made in 277, 303, 313, 318 and 326 cu in versions. The 326 was one year only used in Dodge and the only one with hydraulic lifters.  The 303 was supposed to be for Canadian Dodge and Chrysler only but was borrowed by Plymouth for the Fury in 1956. 313 was Canadian and export only. I think there was also a Canadian 315.

In 1957 they brought out the 318 in 3 versions,  with 2 barrel carb, 4 barrel carb, and the V-800 290HP Fury engine with 2 4 barrel carbs. The V-800 was offered only in 1957 and early 1958.

The reason was, in 1958 they brought out the new B engine or big block. This was an entirely new engine of conventional design with wedge heads and valves all in a row. It was very light and compact for its size, barely larger than the poly 318 and fit easily in its place. This became the performance engine from then on, and the poly was relegated to workhorse duty in sedans, station wagons and pickup trucks. The 2 barrel version was used in millions of cars, there was a 4 barrel option but they did not push it, and it was quietly dropped after 1962.


So the 318 was neglected in favor of the 383 413 426 and 440 B and RB engines. In recent years a few people have taken a second look at them. They found a very good head design, with bigger valves and other advantages over the wedge head LA engine that came later. On top of a very strong block with forged crankshaft and other quality features. Things like bearings, timing chain and gears, oil pump, basically the whole bottom end interchanges with  the later LA 318. A few guys have gotten well over 400HP out of them using the standard hop up tricks.


There might be some demand for intake manifolds for single and dual 4 barrel carbs and maybe 3 2's for the nostalgia hot rod crowd. Even though they made millions of them and plenty are still around, there isn't much interest in them. It would be a fun project and you might sell a few but not enough to make any serious money.

Edited by Rusty_OToole (see edit history)
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As far as speed equipment goes the camshafts are unique with different valve arrangement than the later LA engine. The cams will physically interchange but won't work because the order of intake and exhaust valves was changed.

There were 4 barrel, 2 4's and 3 2's available at one time from aftermarket sources as well as from Plymouth. It should be possible to get specimens, scan them and create molds for new castings.

Distributor interchanges with later LA engine if you want electronic ignition.

The old block has been fitted with later long stroke 360 and aftermarket crankshafts and rods although, I am not sure if they need to be modified, the 318 and 360 may have different size main bearings.

One of the header manufacturers could make you some if you made it worth their while, not sure how many sets they would consider worth tooling up for.

Pistons can be made, basically the same as later 318s but with different valve notches. There are different piston manufacturers who could accommodate you.

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Good Evening All,


Thanks for the input. I have been researching the "A" engine for several months and searching for performance parts for them.. I have seen several requests for parts for these engines as well. I would say that the lack or a solid supply of parts has hindered the interest for people to take this engine family seriously. Like anything, the path of least resistance is the one most people will take. But when you consider you can get 500HP and 500FtLb of torque out of the engine you already own should be very appealing. And when you consider that these were used in dragsters back in the day should help give you assurance that it is a robust base for a performance build.


I was hoping I could get some hard numbers of how many were produced. I could then do some fancy calculations to determine the potential market for aftermarket parts. Lets be serious for a second, there are still thousands upon thousands of these still out there.. Our younger enthusiasts that are hitting the seen could have an opportunity to acquire a reasonably priced vehicle that has the potential to "Hop-Up" the existing powertrain without breaking the bank. 


I am looking for any of the performance intakes and any other goodies that you may have buried on a shelf that I could use to develop tooling for and upgrade for improved performance. I have the capabilities to do all the aluminum castings (including heads with thicker walls for porting. I can also do Headers, pistons, cams, cranks, rods.....) and all of the finish machining.


Any help I can get to source some of those old parts would be greatly appreciated.


Thanks Guys and Gals.


Stay Safe



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Great information Bloo.  I have a 59 Fargo 1 ton ( Canadian Dodge) that would have had a 313 originally, but I would bet that it is now a 318.  a lot were swapped if a short block was required. 

Its a great engine for that truck.  

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Production numbers hard to come by. I did find number of Dodge and Plymouth cars sold on the Allpar site. Adding up each year, from 1956 to 1966 I got a total of 2,662,210 Dodges and 4,892,742 Plymouths for a grand total of 7,554,952 cars not counting Valiant, Dart, or Barracuda which never used the wide block engine.

I am going to guess that 80% of these full size cars got V8 engines and more than half were A engines. Say, 50% of these cars had A engines. I think that is conservative. That would give us a total of 3,777,476 A engines and that is just the US. Canada produced about 1/10 as many cars and more of them were six cylinder cars, still I would not doubt there were another 250,000 made in Canada.

So far we have not mentioned trucks, buses, motorhome chassis etc. Could they have made half as many of those? Or let us say, one quarter as many.

That would give a grand total of 5,000,000 produced. I admit there is a lot of guess work in there but I don't think it is far wrong. If anything it is on the conservative side, as regards trucks.  I did not even mention the number exported around the world including  150 a year they sold to Bristol  lol.


How many survive? Probably not too many after 54 to  65 years. Maybe 10% or 500,000. How many owners want to hop them up? Not one out of a hundred I should imagine. You might be looking at sales in the hundreds but whether it would be 100 a year or 500 I couldn't guess. Even that might be optimistic and the number will diminish each year as they get older and more obsolete.

Edited by Rusty_OToole (see edit history)
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