Unidentified Engine... Anyone Know What This Is?

Chrysler Marine used them and had 4 barrel intakes right up till the last year the engines were made.Four barrel intakes in the cars were ended in 62. Marine s****yards are a great source for poly 4 barrel intakes.

 

Here's the info i was going off of. Note the sources provided at the bottom, especially #2..

Differences Between Poly "A" engines and LA engines

•Heads are very different:
◦Intake and exhaust arrangement for the Polys is I-E-I-E-I-E-I-E, where the LA/Magnum arrangement is E-I-I-E-E-I-I-E.
◦Poly valve arrangement is canted with intake and exhaust valves angled opposite each other, while LA valve arrangement is wedge style with all valves aligned in a row at the same angle.
◦Poly heads have the intake valves on one side of the rocker shaft and the exhaust valves on the other side, while LA engines have all of the valves on the same side of the rocker shaft.
◦Poly and LA Rocker arms are different.
◦ Poly heads are much heavier than LA heads.

•Valve covers are different: ◦Poly valve covers have two bolts in the middle of the cover. LA covers have five smaller bolts around the outside edge of the cover.
◦Poly valve covers are also scalloped at the lower edge, while the lower edge of LA valve covers is straight.

•Pushrod angle is different. Poly 318 blocks had the original 59 degree lifter angle to work with the Poly heads, so the pushrods are much closer to being in line with the lifters than in LA and Magnum engines. Because Chrysler carried over the basic Poly block design with different head designs for the LA and Magnum families, the pushrod angle is much worse.
•Poly blocks are different (although they will accept LA heads): ◦Poly blocks have deeper reliefs on the intake side of the deck to clear the straighter pushrod angle required by the Poly heads.
◦Poly blocks are a bit heavier due to their non thinwall castings.
◦Poly blocks can sometimes take up to a .130 overbore - much more than LA blocks.
◦There is a possibility that one bolt hole in the bellhousing area may be a little different on earlier versions.

•Poly and LA camshafts are different due to the different valve arrangement
•Poly lifters were solid. Except for early LA 273 engines, all LA lifters were hydraulic.
•Poly "A" Pistons are different due to the different cam timing, so the valve reliefs are in the wrong places for LA engines.
•Intake manifolds are different
•Exhaust manifolds are different

Similarities Between Poly "A" engines and LA engines

•Poly "A" blocks can be used with newer LA and Magnum heads.
•Transmission bellhousing bolt pattern is the same.
•Crankshafts interchange with 273/318 and internally balanced 340 LA engines.
•Oil pump and distributor drive shafts are the same.
•Oil pans from 273/318/340 LA engines will fit
•Dampers from 273/318 and internally balanced 340 LA engines will fit.
•Distributors from all LA engines will fit.
•Poly timing chain and sprockets are the same as LA engines.
•Poly block deck height, bore spacing and 59 degree lifter angle are the same as LA blocks.

Will Poly Heads Fit an LA Block?

Because of the deep reliefs required in Poly blocks for the straight Poly head pushrod angle, it is not certain whether Poly heads will work on LA blocks. Poly heads definitely won't work on Magnum blocks, because they are oiled through the deck, and Magnum blocks usually don't have the required oil p***ages.

Poly Aftermarket Support

There is not as much aftermarket support for Poly engines as with the LA and Magnum series engines, but a few manufacturers are now offering parts for them - notably TTI with their excellent headers. They are not cheap though. The Poly engines will also accept the 4" cranks, which are now the rage with the Poly enthusiasts. Properly set up, they can make some serious power.

Sources:

•How to Build High Performance Chrysler Engines by Frank Adkins
•Small Block "A" Engines - Mopar Performance Parts
•Polyspherical Engine ***ociation
•1962 to 1965 Mopar Site
•Moparts members Dogdays, Supercuda and Hotroddave40
•Farley's member Patrick

 

There are worse hobbies you could
have. At least I'm pretty sure there
are, anyway.

Mart3406
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Will Poly Heads Fit an LA Block?

Because of the deep reliefs required in Poly blocks for the straight Poly head pushrod angle, it is not certain whether Poly heads will work on LA blocks

This has been covered before, Yes they can be made to work; NO, they are not a 'bolt-on'.

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Thanks everyone for the great information! Looks like I'm going to be going back for a poly block! And yes, there are worse hobbies. Collecting dead ******s, for example. I think in comparison, my wife should be THANKFUL...

 

Desoto's ran the Dodge 325 poly engine in 1957 in their Firesweep models
and ran the hemi's in all other models esp from 1954 onwards. They did run their flathead six up till 1953 but thats not what we are discussing here. The main answer is that Desoto used the Dodge Poly engine in 1957

 

46-8 Plymouth would've come with a straight 6, definitely a transplant.

 

----------------------
I like the way you think!

Mart3406
==========

 

I know this will be slightly OT...can someone school me on the 318-3 engine, have been offered one from a D-600.....only 40,000 miles on it, the truck has been in storage for many years. I'm not concerned about what it is worth, I'm getting the engine for free, the guy just wants to s**** the rest of the truck.

 

If my memory serves well a 318-3 is a LA 318 ci engine with tougher internals for truck work. They had a slightly stronger crank through Nitrating the journals (?) and everything was checked and double checked to make sure the engines lasted in heavy industrial applications. It will have a lower compression than a car engine however its still a LA 318 engine so all parts will interchange with a standard engine.

 

This is the poly I wish I had in my 56 Custom Royal. You have a separate intake and windage tray, this engine can be converted to Hemi quite easily, quite desirable.