Curbside Classic: 1956 Chrysler Windsor (and the Poly Engine) – The Semi-Hemi

windsor lead view

(first posted 1/31/2015)    The 1956 “Power Look” Chrysler Windsor debuted just over 16 years before I did, representing a light update the 1955 “Hundred Million Dollar Look” Windsor Deluxe, as spotted by our own J.P. Cavanaugh last year.

There really was a new name for the Chrysler lineup every year, then.

windsor grille

The main change in appearance was a new grille for the Windsor—the higher-end cars kept the gridwork double grilles from 1955.

I searched for “1956” on a popular free classified ad service the next day and saw this very car for sale at $5500. An exhaustive search of the same service on the same day indicated that the Windsor is a bargain for a 1956 car, compared to a couple similarly priced engine-free Bel Airs sitting on a patch of dirt just barely on the right side of the junkyard fence.

windsor dash

There are signs of practical, economical restoration here: the original seat is re-covered in durable velour-type fabric. (It looks like mainly the excellent dash came out in the photos, though… Could that be the original radio?)

windsor rear

I think I like the painted rear bumper. Re-chroming is expensive, and the big chrome bumpers on 50s cars don’t do much for me.

windsor passenger quarter

Gray isn’t the most exciting color, but in this case, the absence of 2-tone and 3-tone, high-contrast paint seems to let you focus on the lines. The passenger cabin is rounded in the rear, in the traditional fashion, but it’s not bulbous looking. Years later, I would be liking the Series 1 Jaguar XJ-6 for having this kind of rounded “C pillar” area.

windsor full passenger profile

The front end of the passenger compartment isn’t quite as neat looking, to me.

This Karmann Ghia is going where the gray monster tells it too...

This Karmann Ghia is going where the gray monster tells it to…

As most folks here know, these cars were the beginning of Virgil Exner’s transformation of the looks of the American fleet. One detail beloved of the House of Exner is the resolution of the front quarters into the cowl and windshield.


And here it is again on the Valiant, altered to accommodate double headlights. My new pet theory about cars is that Exner-styled cars of undeniable, uncontroversial beauty would have taken over the world if the man hadn’t been required to design fronts for 4 headlights. He just couldn’t make himself de-emphasize the width of the goggle eyes.


Uncontroversial, I was saying? Oh, right, I’ll sit back down.

windsor door handle

Nevertheless, I really like this Windsor, right down to the door handles JPC noticed on the 1955.

In addition to bold new styling, Chrysler was expanding its powertrain portfolio in the 1950s. 1956 was the last year for the 2-speed Powerflite transmission in the Windsor series; the 3-speed Torqueflite was first offered in the 1956 Imperial, and spread through the lineup in 1957. Chrysler also built a dedicated engine for the Windsor, and other humbler cars, beginning in 1955: the Spitfire Poly.


Engine 331ci Hemi Cut Away #2a Chrysler Fire Power 1951

The original, 1951 Chrysler Hemi V8 is an engine with enough logic behind it to be understandable to people (like me) with limited understanding of the internal combustion engine.

“You want a cross-flow head, overhead valve engine? This is what it’s gonna look like!” Intake valve with a blue port, spark plug in the middle, exhaust valve with a purplish-red port. If you compare the pushrods in the left bank and the right bank, you can see there are two types of action, intake valves with rockers being pushed up toward the center of the engine (left), and exhaust valves with rockers being pushed down toward the ground (right). To hold the two rows (per bank) of rockers all in place, there were two shafts. The result was a big, heavy, expensive engine.

The Polysphere V8 was built off the same block as the Hemi (this is not true, of course, of the “A” Poly engine, originally created with Plymouth in mind and produced 1955-1966).

polysphere A-enginesimilar Plymouth/Dodge A-Engine Polysphere

The Poly provided a semi-cross-flow head with a single rocker shaft. The rockers for the exhaust valves are much longer than those for the intake, and the result is two separate rows of valves but one shaft. The other difference with the Hemi, also visible here, is the sparkplug near the bottom of the head.

Project car hell for MPLS Cafe Racer, on

Project car hell for MPLS Cafe Racer, on


Compared to the Hemi, the Poly had less area in the head for a combustion chamber, and consequently smaller valves. Both the Hemi and the Poly went against the grain of most American OHV V8 engines, which had their valves all in a row.

Chrysler B RB big-block-V8

Beginning in 1958, Chrysler’s new flagship engine, the “B” (and the bigger “Raised B”) would continue the horsepower wars with the weapons of MoPar’s opponents: inline valves and higher compression. The wedge head of the B/RB engine would generate high compression through “squish”: a near-meeting of a flat piston top with the bottom compression chamber surface can concentrate, or squish, the fuel-air mix, for more complete combustion. There’s not a single recorded statement, that I could find, anyway, lamenting the loss of the Poly head design. The B-RB engine, and then the Light A (LA) wedge-head re-working of the smaller Poly “A” engine, created more horsepower per dollar, something that both manufacturer and buyer could appreciate.

The wedge heads in these engines were cheaper to make, lighter, and performed better. This quote from Chrysler Engine Development Engineer Pete Hagenbuch puts it succinctly:

..the performance improved by getting rid of the silly polysphere. A wedged chamber have some advantages… you can build in a lot of what we call squish, where the chamber is just part of the cylinder head surface and the piston has a flat area that matches up with it. Squish is why you can run 12:1 on a wedge head because without squish you would have to run 9:1. It gets the charge moving and mixed, moving through the chamber at high velocity, which means the flame travel is fast and there isn’t anything left to burn by the time it gets to top dead center where you expect the detonation. Anything that reduces detonation also helps reduce pre-ignition which is catastrophic.

The poly turned out to be as much of a dead end as the original hemi (except for racing and all-out performance use).

The 1956 Windsor’s 331 Poly made 225 HP with 8.5:1 compression, running through a 2-speed Powerflite transmission.

windsor driver profile

With a little effort on my part, I think it would be able to run pretty hard on those slot-mag shoes. Unfortunately, both spots in my apartment’s mercifully enclosed tandem parking are full. Your basic 21st century combination of professional school loans, and probable neighbor hostility to the inevitable wrenching activities, put this beauty in somebody else’s care.

windsor mirror

I hope they’re thorough enough to figure out the final question: is this interesting mirror mounted correctly?