booker t jones
Well-Known Member
if so whats good about it whats bad about it
any body running a poly 318 in their car
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Video: What Is A Mopar 318 Polysphere And How Come Nobody Likes It? - Street Muscle
Pretty neat read above. Essentially heavier than an LA, but have a head design similar to early hemi's. I believe a member on here has a turbo poly. Lack of avail performance parts scare most away, and dollar for dollar you would be hard pressed to compare it to an LA.
Pretty neat read above. Essentially heavier than an LA, but have a head design similar to early hemi's. I believe a member on here has a turbo poly. Lack of avail performance parts scare most away, and dollar for dollar you would be hard pressed to compare it to an LA.
racerdan80
Well-Known Member
They were good engines for many years. Mopar needed a smaller economy car and the Poly was too big. It was the original A engine. Mopar designed the 273 and called it the LA (lightweight A) which was smaller and could fit in the smaller A body chassis of the Darts and Valiants. There has been a surge lately in Poly performance with the new intakes and accessories made by Poly Super Pac. Some 318's have dyno'd at over 400 horse. Poly
Without some cutting and hacking, the poly won't like it under the hood of your Mopar. You can make anything fit but it might not be fun.
Without some cutting and hacking, the poly won't like it under the hood of your Mopar. You can make anything fit but it might not be fun.
abodyjoe
Well-Known Member
its big and bulky, very few speed parts for it. an alumn 4bbl intake for it will cost 400-600 dollars headers are few and far between. just seems like a waste tome..
they are making stroker kits, cams an new alum intakes for them though. not cheap like stated though..
my 65 D100 has one. pretty ballless but i haven't really had the cance to mess with it because of the darts engine swap..
they are making stroker kits, cams an new alum intakes for them though. not cheap like stated though..
my 65 D100 has one. pretty ballless but i haven't really had the cance to mess with it because of the darts engine swap..
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booker t jones
Well-Known Member
I got one in a car I just got this 1st one I ever saw and I'm 70 original to this 66 coronet
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booker t jones
Well-Known Member
my initial thought toss this and put in a built 318 904 3.91 suregrip but now thinking survivor car
Clean things up under the hood and drive it. It will probably get you darned near 20 mpg. highway.
Turbo poly
Oz Charger
I have one in my OZ Charger ( A Body ) What's good / bad , I like the look of them 
They are very smooth and quiet , after market parts seem to be more plentiful now with there new found popularity ... ( though limited )
I have fitted a Turbo to mine , seems to have woken the old girl up quite a bit .
They are very smooth and quiet , after market parts seem to be more plentiful now with there new found popularity ... ( though limited ) I have fitted a Turbo to mine , seems to have woken the old girl up quite a bit .
booker t jones
Well-Known Member
appears to be a new ignition switch hooked up but not put back in dash yet put a hot battery in it not a click so I guess next logical step hook up battery go under car and see if starter working by crossing the posts
GTGrinly
Well-Known Member
I put one in a 66 Dart in 1971, was the only motor I could come across when the 273 blew. I didn't have to cut or hack anything.
They are big and bulky only because of their heads. The block is almost exactly the same size as a small block.
The small block 4" stroker crank is also a DIRECT drop in, plus they bore easily to 4", so a 402 cube poly engine can be made easily.
The heads are the good thing. They are arguably better than the LA heads with some larger valves and mild port work.
Here is some good info on them.
Building a Polyspherical (Poly or Polyhead) 318 Mopar Race Motor
The small block 4" stroker crank is also a DIRECT drop in, plus they bore easily to 4", so a 402 cube poly engine can be made easily.
The heads are the good thing. They are arguably better than the LA heads with some larger valves and mild port work.
Here is some good info on them.
Building a Polyspherical (Poly or Polyhead) 318 Mopar Race Motor
Very interesting.
abodyjoe
Well-Known Member
Yes I know it's all in the heads. But doesn't change the fact that it's big and bulky.
The stroker kits are cool. There's a few out for them. Damn intake is $600 for the latest alumn one that's out. The old 7503 I think it is, from weiand is about $500 unless you get real lucky and find someone that doesn't know it's worth. Even a cast iron factory is going for $300 plus. I got lucky and grabbed one cheap.
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OK, I had to stop reading the replies due to outright wrong statements being made or assumed or just not exactly accurate.
Facts
The Poly is a only a few pounds heavier. Not a whooping 30, 40 or 50 pounds.
The block is the same as an LA in width height and depth.
It lacks a few freeze out plugs.
The abilty to bore it out to 4 inches has been done with good cylinders all thickness reported.
The heads are bulky vs. an LA as well as heavier.
The intake attaching surface is wider looking due to an angle change.
Where the heck is that thread where I had the two engines side by side and showed the swapping of parts?!?!?!
I did it years ago. I should have made a thread on it.
This always pops up from time to time with the same old things being said.
Facts
The Poly is a only a few pounds heavier. Not a whooping 30, 40 or 50 pounds.
The block is the same as an LA in width height and depth.
It lacks a few freeze out plugs.
The abilty to bore it out to 4 inches has been done with good cylinders all thickness reported.
The heads are bulky vs. an LA as well as heavier.
The intake attaching surface is wider looking due to an angle change.
Where the heck is that thread where I had the two engines side by side and showed the swapping of parts?!?!?!
I did it years ago. I should have made a thread on it.
This always pops up from time to time with the same old things being said.
booker t jones
Well-Known Member
so after 50 years are these engines easy to find hard to find expensive or inexpensive I'm 70 been in mopars 50 years first one ive encountered
abodyjoe
Well-Known Member
i just picked one up for $100.. they still aren't very popular. but do have a little following..
...
MopaR&D
Nerd Member
IIRC in my Chrysler Engines 1922-1998 book, Willem Weertman says they reduced the weight of the LA by 25 lbs. compared to the poly/A engine.
The Poly is cool to me just because it's different and the combustion chamber design is more efficient than a wedge, meaning the fuel economy is better and it takes less mods to make more power (in theory). Like rumblefish said it's also an old-school thick wall design so the cylinders can be bored over a huge amount.
If you already have a car with one in it I'd say go for it, maybe get it running nice in that Coronet and find out how good it is then go from there.
One thing to note the later A-bodies are wider and can probably fit a poly easier than the early A-bodies the LA was originally designed for...
The Poly is cool to me just because it's different and the combustion chamber design is more efficient than a wedge, meaning the fuel economy is better and it takes less mods to make more power (in theory). Like rumblefish said it's also an old-school thick wall design so the cylinders can be bored over a huge amount.
If you already have a car with one in it I'd say go for it, maybe get it running nice in that Coronet and find out how good it is then go from there.
One thing to note the later A-bodies are wider and can probably fit a poly easier than the early A-bodies the LA was originally designed for...
72SwingerJosh
Well-Known Member
My uncle had one in his 57 fury that had the factory dual quad intake and was rated at 290hp which is the same horsepower the 340 ta six pack was rated. He said it was a real screamer of an engine. And would make the car fly.
I'll say for the most part there cheap, very, but not always because some people think there worth there weight in gold.
The only performance part that can not be found at all are heads. No such thing exists to my knowledge. Pistons must be custom made.
Above is the only NEW intake for a poly. Pricey but very nice.
All other parts can be found BUT they may not be a bolt up to the other parts compatable. This I am fuzzy on. Check crank registers for transmissions.
booker t jones
Well-Known Member
haven't actually heard this car turn over yet supposed to bring it home today my plans for now is keep the car as a survivor the bright work is absolutely perfect on this car the paint no rust no dents but faded and wore thru in spots haven't checked yet on 66 are build sheets normally under back seat which probably ha never been out of car always cool to see what you when you take it out
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