Poly Engine what was good/bad about it and why is the LA better?

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Can somebody post a shot of an assembled poly engine with the stock valve gear without the valve covers on?

I had a 64 Dodge 440 2 door sedan for many years. The poly 318 had gobs of low end torque and made a great solid driving engine. A friend from Vancouver Island BC used to drive down to Seattle for Mopar Drags at Bremerton Raceway and the back-to-back Spring Round-up car show in his 63 Plymouth B-body. He drove hundreds of miles to get there, bolted drag radials from the trunk and ran 13.00 super consistently all day, often winning the days bracket race, then swapped tires and almost always took his class at the car show the next day, then hundreds of miles home. The engine? 318 poly with dual quads on the factory cast iron manifold.
 
str12-340 said:
Can somebody post a shot of an assembled poly engine with the stock valve gear without the valve covers on?

I had a 64 Dodge 440 2 door sedan for many years. The poly 318 had gobs of low end torque and made a great solid driving engine. A friend from Vancouver Island BC used to drive down to Seattle for Mopar Drags at Bremerton Raceway and the back-to-back Spring Round-up car show in his 63 Plymouth B-body. He drove hundreds of miles to get there, bolted drag radials from the trunk and ran 13.00 super consistently all day, often winning the days bracket race, then swapped tires and almost always took his class at the car show the next day, then hundreds of miles home. The engine? 318 poly with dual quads on the factory cast iron manifold.
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I was going to call BS on your post until I remembered that In high school a friend of mine had a 66 Satellite or Belvedere ?? with the poly 318 2 barrel, I wasnt impressed until he smoked tires all the way across the senior parking lot.
 
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Just for grins, here's a set of Ballenger headers for the 318 poly from the late fifties. Note the generator bracket (on early poly motors, the generator bracket was part of the passenger side exhaust manifold casting).

Ballenger header 318 poly 2.jpg

Ballengerheader318poly.jpg
 
cudamark said:
The cranks are not the "same". You can interchange them with some caveats. The convertor register is a different diameter, so, you can put the 318 crank into the 273 if you use a reducer bushing for automatic applications, and you can put a 273 crank in a poly 318 application if you machine the crank register to accept the 727 converter button. Manual trans isn't an issue unless you're going from auto to manual on the swap. Then you need to check to see if the pilot hole got the final machining for the bushing, or, you'll need to use the magnum bearing or make a custom bushing as the case may be. Also, the crank swaps should require a rebalance due to the difference in piston weights. This also only applies to the '62-7 polys, as the '61 and older had an extended 8 bolt crank flange.
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Oops, forgot about the smaller register of the early 273's. One interesting factoid: When I swapped a later 225 into my 65 Valiant, I had to open up the pilot hole in the flywheel to fit over the later crank. But when I swapped a 340 into my 65 Barracuda, the 273 flywheel fit perfectly as is. I haven't had a 273 crank to eyeball in almost fifty years, but I assume from the foregoing that the early 273 crank register has the same outside diameter as the later ones, but a smaller inside diameter?? So it could be machined to clear a later torque converter?

Anyway, as to balance, according the Hot Rod's December 63 article about the new 273, since the 273 crank and rods were the same as the 318, but the pistons were lighter, "an extremely heavy-walled piston pin is used in the 273 to bring total reciprocating weight up to that of the 318. This eliminates the need for special balancing. . . ."
 
S'cuder said:
I'm pretty sure in the book, Christine's engine was a dual quad 318 Poly.
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There are a few foibles in the novel, Dennis (narrator of the story) said "Like the 382's they used to put in those old cars. Like Christine.", & "He dropped the hydramatic into D". Also indicated 1 4bbl when They discovered the car, later "318 painted on the air cleaner" post "resto"...given that, I have an appreciation for Carpenter's crew, doing the movie Christine w/the top of the line '58 engine combo accurately.
 
Oh, Dennis wheeled a Duster, not a Charger in the book.
 
65 Cuda 340 said:
Oops, forgot about the smaller register of the early 273's. One interesting factoid: When I swapped a later 225 into my 65 Valiant, I had to open up the pilot hole in the flywheel to fit over the later crank. But when I swapped a 340 into my 65 Barracuda, the 273 flywheel fit perfectly as is. I haven't had a 273 crank to eyeball in almost fifty years, but I assume from the foregoing that the early 273 crank register has the same outside diameter as the later ones, but a smaller inside diameter?? So it could be machined to clear a later torque converter?

Anyway, as to balance, according the Hot Rod's December 63 article about the new 273, since the 273 crank and rods were the same as the 318, but the pistons were lighter, "an extremely heavy-walled piston pin is used in the 273 to bring total reciprocating weight up to that of the 318. This eliminates the need for special balancing. . . ."
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Yes, same outside diameter to match the inside diameter of a flywheel, but, the inside diameter is smaller on the 273 for the early 904 converter button. And as I mentioned, the cranks that came in a manual trans car were finish machined for a pilot bushing. Most automatic cranks weren't. With a 318 crank, that's no big deal because a Magnum pilot bearing will work fine in the big register. With a 273 unfinished pilot hole, that bearing won't fit, so, you either have to machine the register hole bigger, or, hone the pilot hole smooth and machine down a bushing to fit. In the times where I swapped cranks between a 273 and 318, the balance was never way off, but, also, never close enough for me. I always rebalance an engine anyway when doing a rebuild, so, not an issue with me. For up to 5000 RPM, sure, probably not an issue, but, higher RPM's with new aftermarket and oversized parts along with machining everything, I feel much better when everything is properly balanced.
 
cudamark said:
Yes, same outside diameter to match the inside diameter of a flywheel, but, the inside diameter is smaller on the 273 for the early 904 converter button. And as I mentioned, the cranks that came in a manual trans car were finish machined for a pilot bushing. Most automatic cranks weren't. With a 318 crank, that's no big deal because a Magnum pilot bearing will work fine in the big register. With a 273 unfinished pilot hole, that bearing won't fit, so, you either have to machine the register hole bigger, or, hone the pilot hole smooth and machine down a bushing to fit. In the times where I swapped cranks between a 273 and 318, the balance was never way off, but, also, never close enough for me. I always rebalance an engine anyway when doing a rebuild, so, not an issue with me. For up to 5000 RPM, sure, probably not an issue, but, higher RPM's with new aftermarket and oversized parts along with machining everything, I feel much better when everything is properly balanced.
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Thx for the early 273 crank register info. As for the pilot hole often being unmachined in an automatic trans crank, that's pretty much true for any of them isn't it? I know my Dad and I had to get a 440 automatic crank machined for a pilot bushing so we could run a four speed behind it.

Edit: that was long before Magnum pilot bearings existed. I see what you're saying, with a later 318 crank you can use the Magnum pilot bearing, but you can't with the early 273 unless you machine the pilot register bigger.
 
For those interested in Polys, check out what all they do at Chrysler Power magazine bunch. They have lots of potential if you want to spend the and be a little different.
 
Spending time at lots of car shows, I am always happy to see engines that are out of the ordinary. A poly make an eye catching power plant in a sea of more typical choices...
 
barbee6043 said:
For those interested in Polys, check out what all they do at Chrysler Power magazine bunch. They have lots of potential if you want to spend the and be a little different.
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Allegedly the blocks are thick-wall castings so they can be bored over quite a bit more than later engines... combined with SBM 4" stroker cranks you can get a lot more than 318 cubic inches. But then of course the heads will need some work to really support it.
 
^^^ There are a couple of poly engine gurus that do the heads and one also has done a new alum. 4 bbl intake . Not cheap but supposed to be a nice improved piece. Sure a guy can make the same HP out of an A motor and cheaper, but that is not the point.
 
65 Cuda 340 said:
Great looking poly! What headers are those? Also, what cam are you running? Thx.
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The headers are custom made. Tried to get them to match up to the stock exit locations. In hindsight, I would have done the passenger side differently.
The cam is from Camcraft. 224/224 @.050" solid .450" lift. 110 degree lobe separation 106 ICL. Very flat torque curve. Over 300 lb/ft from 3000 to 4500 rpm and still pulls hard on the top end.
 
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str12-340 said:
Can somebody post a shot of an assembled poly engine with the stock valve gear without the valve covers on?

I had a 64 Dodge 440 2 door sedan for many years. The poly 318 had gobs of low end torque and made a great solid driving engine. A friend from Vancouver Island BC used to drive down to Seattle for Mopar Drags at Bremerton Raceway and the back-to-back Spring Round-up car show in his 63 Plymouth B-body. He drove hundreds of miles to get there, bolted drag radials from the trunk and ran 13.00 super consistently all day, often winning the days bracket race, then swapped tires and almost always took his class at the car show the next day, then hundreds of miles home. The engine? 318 poly with dual quads on the factory cast iron manifold.
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Amazingly, I did not have one from my engine, but here is a good shot of the valvetrain.
poly head.jpg
 
MopaR&D said:
Allegedly the blocks are thick-wall castings so they can be bored over quite a bit more than later engines... combined with SBM 4" stroker cranks you can get a lot more than 318 cubic inches. But then of course the heads will need some work to really support it.
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They are really thick wall castings. They can be taken to a 4.00" bore very easily.
 
Killer6 said:
There are a few foibles in the novel, Dennis (narrator of the story) said "Like the 382's they used to put in those old cars. Like Christine.", & "He dropped the hydramatic into D". Also indicated 1 4bbl when They discovered the car, later "318 painted on the air cleaner" post "resto"...given that, I have an appreciation for Carpenter's crew, doing the movie Christine w/the top of the line '58 engine combo accurately.
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I remember that. I went looking for the book, but it wasn't in the most likely spots, so after a half hour I gave up. The 382 I just figured was a typo. My daily driver at the time was a 383 RR. I looked up the 318 in a Chilton's book, and saw they had 2-4 bbls in the '58 Fury. So, King used some artist's license, and Carpenter did too. At least King didn't flip out over the changed ending, like he did over Kubrick's The Shining. Regardless, it's one of the best horror movies ever.
 
Very similar. Thick wall castings, a little more material in the bellhousing area and maybe the lifter valley. I haven't measured that, but it does look beefier. Doesn't have as many freeze plugs as the LA. Chrysler changed very little to adapt to the LA. It's why the LA still has the 59 degree lifter angle. They are much more of a straight shot to the rockers on the poly.
 
Killer6 said:
There are a few foibles in the novel, Dennis (narrator of the story) said "Like the 382's they used to put in those old cars. Like Christine.", & "He dropped the hydramatic into D". Also indicated 1 4bbl when They discovered the car, later "318 painted on the air cleaner" post "resto"...given that, I have an appreciation for Carpenter's crew, doing the movie Christine w/the top of the line '58 engine combo accurately.
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King didn't know anything about Plymouth Furies, just thought "Fury" was a cool name for a monster car. So, he didn't know that the 56-58 Furies (is that the plural of Fury?) were each a special model, each available only in a special Fury color. I.e., no red 58 Furies (or 56 or 57). Also didn't know that ALL 57-58 Furies had two four barrel motors, whether 318 in 57, or 318 or 350 in 58. Later ones - all colors, and single two and four barrel motors. But not 58. Also, of course ALL 1958 Chrysler products with automatic transmissions had push button controls, not column shifters, and they weren't called Hydramatics (GM), and they didn't have push button inside door locks (you moved the inside door handle forward to lock it from the inside).

All those mistakes plus the number of 58 Plymouths that got wrecked in the making of the movie pretty much turned me off. Jeez, if you're gonna write a book whose main character is a 1958 Fury, then do some basic research about the car. But I know a lot of Mopar fans like the movie. Maybe because there are so few movies about Mopars?? (Vanishing Point??).
 
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