Poly vs Hemi Mopar engines!!!

Someone was playing in the dead threads. A "Serious" "A", be cool to stroke & bore it out to 402 with the 2X4 intake & chromed valve covers! I'm busy shoehorning a 331 Hemi into a '60 Plym.

 

Nothing wrong with bringing a thread back from the dead!!

 

Last one of these motors I had was in a 61 Dodge Phoenix (Dart) with a automatic. It has 287,000 on it when I sold the car and it still ran great yet. It 98,000 when I bought it. Bone stock 230 h.p. 2bll Stomberg and then later a Carter carb. It was a 4dr. and had 3:23 gears and would consitantly pull 19-21 mpg on the highway @65-70 mph. It was one of the most dependable cars I ever owned. Had quite a few early Dodge pickups with these motors in too and they never let me down.

Michael

 

Like George says, the OP was dealing with the Hemi based polys not the A series. Yes there is a huge difference.
This subject has been covered many, many times since the OP posted this one. Use the search ****on.

Ok folks, move along, nothing to see here, move along....

.

 

Like George says, the OP was dealing with the Hemi based polys not the A series. Yes there is a huge difference.

Excuse me. G Palovich and the 62 65 website is mentioned several times. That is directly 318 and nothing else. Some of the Chrysler engine use the same bearing rods and mains. it is comon to use a 340 style pump on a hemi or similar poly. Timing chain sets are used often from LA series engines. While the engines look differnt the basic design is the same. What is wrong with discussing a 318? Is there a law or something? It is a poly and in fact is the best known poly. Re the 402 I am not a great fan of the 4 inch stroke. I have done the 3.58 stroke and like it better if you are gonna stroke. Used to do 060 over 340s with offset ground 360 crank (.020 for 3.6 stroke)with reduced main size (318/340 size)for 380 cubes. Long before momma mopar produced these cranks. In fact there is one under my bench right now still that belongs to my nephew. I prefer a stroke less than bore size and ideally would like 90%. Ok Herman I will settle down a bit. Nice carb set up BTW.
Don
Ok so someone posted then ducked out. I entered . What can I say. Got ****ed in again! I love polys. All of them 318s 301s 354s etc etc. Some of us are interested in this subject If you arent then you move along. Why would you keep coming to a thread that doesnt interest you? I just bought one last week . It is kinda a subject now dear to me. Just cause it has been discussed before ??????? so what? You dont have to read it.

 

DaMMIT, I want one now Seriously, Rocky

 

Somewhere in my old mags I have a pic I found of AJ Foyt in a sprint car with a 318 poly. Biggest bugaboo is lack of a real decent serious intake manifold. I have heard of some guy who adapted a Ford small block intake and that might be a decent option if the port spacing is in the ball park. they are certainly narrower so you would have the Wiggle room. A tunnel ram version might be an option there. Some guys have built sheet metal intakes and Gary P has sent me in the past pics of some of that stuff. Just suppose that stuff had been available. These engines would be a lot more poplular. Still making an intake as we have seen many times on the HAMB (even for a sbc) is well within ones ability if you have the patience for it. With the 318 poly like the SBc and Ford smallblock first you need a thermostat housing and water connection p***age and a valley tray. Once that is done it is U fab time. I wish iknew more about resin casting. That i think would be easier to do. I also think Resin manifolds are an imporvement. No shrink, Or so I read anyway , no big foundry furnace needed with a 30 lb crucible etc. Just make a mold and mix and pour. Anyway, when my poly arrives i will set it in the ch***is and that will be my very first project on it. I will know better then. I did a simulator work up on the build with a 780 carb and single plane intake. .It looks good power wise. I am aiming for 7000RPM with stock stroke and bigger bore. Lift around .550"
Don

 

Any Hemi-based Poly uses the Hemi intake and exhaust manifolds and cam gear. The intake ports are the same configuration in both heads. Headers won't interchange because of the different angle of the exhaust manifold surfaces.
The only diff in the blocks is a reshaping of the pushrod holes to accommodate the different pushrod angle on the exhausts, that can be fixed in a few minutes with a die grinder.
I have a soft spot for Poly's, had a few of 'em, great torque monsters! A '57 Chrysler Windsor 4-door HT was a favorite, spun many a tire to ribbons with that old girl.

 

Both the 354 Chrysler and 325 Dogge Polys are
very cool. Both can be made to produce good
power and are definitely "dare to be different"
enough to be worth building and putting into
a rod. (Nobody'll ever confuse it for a SBC or
accuse you of running a 'belly-****on motor'!)
A word of caution though - a lot of people here
have posted stories and info relating to the 318
Plymouth Polys - and just so you know - the 318
Poly (starting with the Plymouth Fury in 1957
and later, also used more or less universally in
Plymouth, Dodge and Chrysler cars after about
'59 or '60) is a completely different engine,
separate from both the Chrysler and Dodge
Polys. The only similarity at all between the
three engines being the basic 'Polyspheric
chamber, single rocker shaft and canted valve'
layout. Virtually everything else is different. The
354 Chrysler Poly was based on the 331-354
Chrysler hemi block, the Dodge Poly on the
on the 315 -325 Dodge hemi block and the
Plymouth loosely-based on the non-related to
either, 303 and 313 Plymouth blocks - and there
is almost nothing that interchanges between
the Chrysler, Dodge and Plymouth Polys.

Mart3406
==================

 

The 315/325 Dodge (Desoto) Hemis and polys are based on the 241/270 engines with a raised deck to accommodate the longer stroke......the Plymouth polys of 241/259 built in '55/56 are also derivatives of the 241/270 hemi/poly Dodges of 53'/'54/'55

Ray

 

----------------
Yeah, 241-259 Plymouth Polys are related
to the low-deck 241-270 Dodge hemis and
polys , but not the '57 and newer 318 Poly.
That's the point I was making. It may not
have been necessary to point that out, but
there is so much misinformation and so
many myths and old wives tales floating
around about these engines that I thought
it would be a good thing to state.

Mart3406
========================

 

Mart, this is the basic idea that George and I were trying to get across without starting a ******* contest. There is already too much confusion in this subject and the new/casual reader will take away much erroneous information from this thread.

Gary

 

I think those power figures are eroneous. My 1962 Motor's Manual lists;

'57 Chrysler 354c.i.
Windsor 285 h.p. - 2 barrel (definitely poly)
Windsor 295 h.p. - 4 barrel (might be poly)
Saratoga 295 h.p. - 4 barrel
New Yorker 325 h.p. - 4 barrel (hemi)
"300C" 375 h.p. - two 4 barrel (hemi)

'57 Dodge 325 c.i.
245 h.p. - 2 barrel (definitely poly)
260 h.p. - 4 barrel
285 h.p. - 4 barrel (definitely hemi)
310 h.p. - two 4 barrel (hemi)
(and also a 354 dual quad with 340 horse)

So now, figure out where the poly leaves off and the hemi takes over. On an interesting note; the Motor's Manual discerns between the two engines by referring to the hemi as a double rocker shaft motor, and the poly as a single rocker shaft motor.

 

Wait a minute! Forget the making a manifold for now! Was visiting an old friends shop today telling him of my Poly rail deal. He had this right in stock! I came home and did a quick layout of the newer spacing for when I pop it on the milling machine. I can go either way here carb wise as I have some old stuff sitting around from days gone by. The Holley though will require an adapter from narrow to wide bolt pattern after opening up the opening to two long wider slots.
The engine and trans I bought is a 1967 Canadian production. (We had both A an LA that year. )It is a 318 which was the last of the Polys from Back in the day. I know , someone will say it s not 64 but it is an engine produced as well then so it is ok. Manifold is from a car not a boat.
I hope to have the engine sitting in the ch***is by Sat so i can dream better.
Don

 

Yea me too. I've owned a lot of MOPAR engines but I haven't found that one yet.

Just for the drama, I personally like the SBC but I have raced Polys and Y Blocks and neither is a slouch.

I never noticed how old the thread was or I wouldn't have chimed in.

 

A couple minor comments...DeSoto Polys were built on Dodge Hemi blocks, but DeSoto Hemis are a family of ther own. The 1st year for Plymouth "A" Polys was '56 when you could get a 277 or 303, + the hemi based 270 Poly, '57 had 277, 301 & 318. The '57 Plym 301 shouldn't be confused with the '55 Chr 301 Poly. See how easy it is to get things confused?

 

Don,
The original 2X4 intakes aren't really that hard to come by. I had one for years, swapped it to a friend, and I know exactly where it's sitting right now. Along with a 3X2 and a factory 4 bbl.... My plan (18+ years ago...) was to convert the 2X4 to port fuel injection and run it on the 381 small block you outlined in an earlier post. Sacrilege, I know, but who cared back then? I paid $50 for it at a swap meet. The guy didn't even know what it was for, but he figured it was worth 50 just because it was a 2X4.

I had 2 of the 318 Polys in 66 Plymouth Furys, and a friend had one in a 65 Dodge Coronet. The guy with the 3X2 had a 318 Poly in a 1956 Dodge P/U and a 315 "Windsor" Poly in a 1957 Dodge P/U. I actually built the 381, but it went in my 68 Barracuda with a set of 340 X heads. I'd still love to try the head swap someday, just to see what it would run like. Sounds like you're livin my dream...

 

Hey George,........I should have clarified the Desoto thing beyond just stating the cu in. I know the Desoto hemis are their own block series. I was referring to the 325 Dodge poly used in Desotos in '57.

Ray

 

I always thought Polys were cool lookin' but never knew too much about them, being a Ford guy, but this "old" "Dead" thread has got me interested and learning a few things. Nothing wrong with bringing one back to the top.

 

This is like a history lesson for a guy like me. Thanks guys.

 

There is plenty more if you stay after cl***, go here.

.

 

I'd only install a Lincoln 317/341/368 "Y"-block in a rod because it has conventional side by side intake ports. not the stacked jobbers of the old 239/312 Ford "Y" engines.

Now back to Poly's, I wish that somebody would create a new read, MODERN poly-head for a SBC as well as the old Jag engine's "May" chambered head.

And one last request is that I wish somebody would create an "LS-" ported head to bolt-on to our beloved SB's. B/M created his SBC block to allow such, but it's NOT a stock block..

I got into a real ******* contest with Tony M. a while back on this subject up to the point of ******* him off.

Ask Tony, he will remember ol' pdq67 getting on his case!!

To this day, I figure that the head sellers are missing the boat by NOT selling a modern LS- ported head that will bolt-on to our SB's.

Sure, we will need intakes as well as exhaust systems, but what the hell if the power production is at least 75 percent of GM's stock hopped up LS- type engines!!

Gotta be a F** money-making proposition by me..

pdq67

 

Sounds like you're livin my dream...
I am doing my best!
Don

 

I hope they used pliers...

 

Oddly enough, I found a company that makes poly heads for B motors. Weird ****, but it was out there.

I posted a link on the Poly Yahoo Group a few years back.

~Jason

 

I'm putting my 325 poly motor in my 1917 dodge cut down touring body with a chevy manual ****** and this weiand intake I just scored. I don't know how much power it will make but with a cam and a nice ignition, I suspect it will scoot a 1500 pound car just fine.

 

Scooby - you find the wildest ****!

 

A ******* contest? Hell, start it. I'll grab a tape measure.

~Jason

 

-----------------
Great!! You do that and I'll sell the tickets
and run the concession stand!

Mart3406
==========================

 

Count me out. I cant be bothered.