What's the deal with the Poly 318

[MarzGraphixDesign]

I've been doing a little reading and, have seen a lot of poly talk lately. I mean SAM entered one in the Engine Masters vintage division. It showed pretty strong at 550hp and 560+ torque. My question is why are they labeled as junk by a lot of us. What is its strengths and weaknesses. Let me know

 

[furyus2]

Imo, it's a good engine. Not popular due to being too large to fit in A bodies. Older technology from the 50's. Now that strokers are popular, you can get the cubic inches needed to make power. I think the head design is good. Check into Gary Pavlovich. He loves these engines, and has done a lot of work on them for years.

 

[stroked340]

They were the "red headed" step child of smallblocks nothing was available performance wise in the aftermarket..in the past few years they've become quite popular,my buddy has 3 in his shop right now that he's stroking for customers..

 

[66fs]

I've been doing a little reading and, have seen a lot of poly talk lately. I mean SAM entered one in the Engine Masters vintage division. It showed pretty strong at 550hp and 560+ torque. My question is why are they labeled as junk by a lot of us. What is its strengths and weaknesses. Let me know

Unfortunately, lots of people voice opinions without knowledge or experience. The Poly engines and early Hemi's are very similar to our over designed LA and big block engines. Not really any weaknesses, other than stated above, lack of High Performance parts and being overshadowed by newer engines. They were never offered in an "A" body. I had one in a push button automatic 64 Dodge Polara and loved it. All Chrysler based engines were way ahead of the competition in design and durability.

 

[perfacar]

I' ve flow tested poly heads before. they out flow any sb head !!!!! had a guy port on one, and flow gain was very big!!! just food for thought.

 

[ssba]

Biggest problem is they became obsolete before the aftermarket developed them.
I haven't had one in a couple decades but I liked them OK.
Couldn't find anything for it. I mean nothing.

 

[RustyRatRod]

That's simple. When people don't know anything about something, it's junk or they are afraid of it.

I would put up a stock poly 318 against a stock 2 barrel 360 any day of the week for pulling capacity and I bet the old 318 would win.

 

[73golddusterkid]

I had a poly in a 65 Sport Fury and with a 2bl carb it ran well! It had no problems cruising on the highway at 70 mph and on a few bonsai runs it reached 115 mph! We eventually had the heads redone and added a Pertronix kit. After those mods it would routinely see 22-25 mpg

 

[MarzGraphixDesign]

very cool on the replies, I was just curious what the word was on them. I have one question on the valve train geomertry, especially on the intake valve that looks like a pretty hefty angle.

 

[1969383S]

A fellow at the Garlits show was dicussing this (maybe Mr. Wolfe) there is a bounty out for making X amount of power from a Poly! Google it I am sure there is plenty out there that I just do not remember!

 

[67Dart273]

In about 1972 my 440 RR with 3.54 gears would run 13.0's

A guy I know had built a "stocker" about a 63 B body with a 2bbl poly. Of course it was not a street car like my RR. So who knows what rear gear, and what had been done to the TF. It ran right with my RR for ET If someone can look up what "then" stock class and the record back then it was alleged to run right on the record for class.

 

[Darter6]

As a kid a neighbor had a 63 Dodge Polara Poly 318.Did the best burn outs at the school bus stop. The photos are from my 64 Belvedere (stupid me sold the car) and it was a runner. Wieand intake 600 AFB and TTI headers and exhaust. Just like the 318 LA's they never got any respect.A friend is doing one that may end up in Chrysler Power Magazine.Back in the day the Poly was often called the Semi-Hemi. Check out the exhaust ports,,,remind ya of the 426 Hemi ?.Great car,stupid owner for selling it..........

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[diymirage]

not really an observation on the potential of the motor...but if your going for looks, about the only thing that will beat nice poly is an early hemi
and it seems you see more of those in show rods then polys

 

[mvh]

One point that wasn't mentioned was weight. The "L" in the LA small block refers to the fact that the block casting was redesigned to be lighter than the old A block. If you're going retro or big inch it's not so much a problem, but it does explain why people don't keep poly 318s in B-bodies. They are strong but heavy.

 

[Infecteddog]

It was the Plymouth small block's pinnacle evolution, which is why it became the corporate small block for so long. While Dodge, DeSoto, and Chrysler had their Hemis- Plymouths got the polys until the big blocks came around. They really weren't bad- just always overshadowed even in their prime. Truthfully in their prime they were superior to most LAs.

 

[67Dart273]

One point that wasn't mentioned was weight. The "L" in the LA small block refers to the fact that the block casting was redesigned to be lighter .

And another minor but irritating point, is "thanks" everybody for not calling them a "wide block," in fact if you tear down an "A" and an "LA" it is not obvious, unless you know just what to look or, what the differences are between the two blocks

 

[threewood]

Heavier block that can be bored out quite a bit. Forged crank.
Big downside is lack of aftermarket. Custom pistons are required if you want anything close to 10:1 Even stock cast iron 4bbl intakes fetch north of $500.

Mine is a beast. Just had Gary Pavlovich and GRC Machine work it over. It is a torque monster and pulls like a jet from 40mph. It has right at 500 miles on it so far. It's no stroker, but has no issue laying down rubber and putting a smile on my face.

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[rumblefish360]

The lack of performance parts when they were new and a few years old is the big issue for them. Now, there is a few more things that you can get and it starts with the big helper in HP, headers from tti & a new intake is available from Chrysler Power. Camshafts are not a problem today as well as most anything else you want for a high performance engine to a light drag car.

As noted earlier, pistons are custom and pricey! Speaking of which, where did you get those slugs from?

 

[barbee6043]

I agree with everyone. great engine, but yes heavy, great for an early B body.
a workhorse. Chrysler Power folks have quite a following, and they are the go to place for parts and info.
a cool looking engine, yes costs more to build than an LA or BB.

its place in performance history it obtained was just due to circumstances of that time.

 

[justinp61]

I had one in a 60 Dodge truck, I rebuilt it when I was in high school, very good engine. IIRC the heads had small runners.

 

[fstfish66]

glad some one finally figured out these engine need some love,,, these heads will fit a modern 273 318 340 360 with a minor modifaction,,one woudl be great in an early A

 

[KENTON]

As a kid a neighbor had a 63 Dodge Polara Poly 318.Did the best burn outs at the school bus stop. The photos are from my 64 Belvedere (stupid me sold the car) and it was a runner. Wieand intake 600 AFB and TTI headers and exhaust. Just like the 318 LA's they never got any respect.A friend is doing one that may end up in Chrysler Power Magazine.Back in the day the Poly was often called the Semi-Hemi. Check out the exhaust ports,,,remind ya of the 426 Hemi ?.Great car,stupid owner for selling it..........

I have that one on my screen saver. I am doing one just like it right now. Same color too.

 

[toolmanmike]

Poly Super Pac is doing a great job with their new intakes and valve covers. Here's some Poly ****:

 

[toolmanmike]

Poly Super Pac is on Facebook. Here's a new post:

Poly Super Pac We've just put together the 'ideal' POLY package... 360 crank with 318/340 mains; .060 over pistons (we have a selection of mild to wild); 360 rods; equals 357MAGNUM... just enough cubes to not demand major headwork but haul some serious mail! Figure right at $1200 for the econo kit and about $1700 for the 'deluxe' kit... Building one now (that's it in photo above) estimating 400ftlb (can also go 402 cubes if you're feeling 'lucky'!!!

 

[Darter6]

Kenton, Thanks.I kick myself for doing that,also for selling my 64 Dart. Hope to see your project soon.