Real reason for the X on the X heads

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1969cuda340

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My Dad worked at Chrysler, about 10 years ago a friend of his that was a VP at Chrysler retores cars and was looking at a Barracuda that the owner said had X heads. He got a kick out of it and reminded my dad why the X was on the heads. Dad could care less about cars but here is the story in his words why the X is on the head.

“The X on 340 CID Cylinder Heads”


The Chrysler Corporation 340 CID engine was an enhancement of its 318 CID engine that had been produced since 1955. Both the 318 and 340 CID engines were concurrently machined and assembled in the Mound Road Engine Plant in Detroit, Michigan. The cylinder head castings for both of these engines were produced by Chrysler’s Huber Avenue Foundry,also located in Detroit.


The 340 cylinder head casting closely resembledits 318 counterpart and was difficult to visually distinguish. The two heads had their specific part numbers cast with 1/4 inch numerals on the exposed surface of the casting, but this difference was not readily discernible. These heads were processed concurrently through the foundry and their similarity in appearance, resulted in the two being mixed when palletized for shipment to the Mound Road Engine Plant. This obviously created a problem.


At this time I was the Product Engineering Manager of the Huber Avenue Foundry. To assist in the separation of these castings, I issued an ‘Engineering Change Request’ that provided for the letter ‘X’ to be prominently cast on the surface of the 340 heads. This change accomplished what was intended. The problem was abated, though I’m sure a few of the 340’s still became mixed with the 318’s on the pallets shipped to Mound Road.


There may be some 340 CID heads out there that do not have the X, but these were produced prior to the change being implemented.


William Kamradt

Chrysler Corporation

1955-1989
 
I'll ask him about the others, he's 85 years old he may not remember. He wrote the piece on the X heads about 10 years ago so he recalled that OK
 
1969cuda340 said:
I'll ask him about the others, he's 85 years old he may not remember. He wrote the piece on the X heads about 10 years ago so he recalled that OK
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That is really a neat story, I have no doubt that your father recollects that correctly. I am often amazed at my elderly father's clear memory of his work days.
 
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Cuda68Scott said:
That is pretty is really a neat story, I have no doubt that your father recollects that correctly. I am often amazed at my elderly father's clear memory of his work days.
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Back then he was really sharp and really still is. I just talked to him and he doesn't remember about the J and other letters, he said that it could of been after he went to another department but clearly remembers about the X heads. Like I said. He could care less about cars it was all in a days work for him
 
ir3333 said:
now that just leaves the J,U,O....year specific?
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1969cuda340 said:
Back then he was really sharp and really still is. I just talked to him and he doesn't remember about the J and other letters, he said that it could of been after he went to another department but clearly remembers about the X heads. Like I said. He could care less about cars it was all in a days work for him
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The other letters are most likely what they used to track the new change levels as they came in...

They also could have ramped up the production and needed to add more molds... They need to identify which mold that they came out of in case any problems arrive, you need to track back what mold they came out of...
 
That's why other parts got easy to ID features. I'm thinking torsion bars for instance.

I've been cleaning up an original set of Rallye wheels this week. Back in the day I mounted a lot of tires part time to earn hobby money. EVERY Rallye wheel I've seen has a yellow paint circle painted on the OD of the rim. I'm thinking they were on some kind of transport or storage rack and the stripe was an easy way to differentiate them from regular steel wheels.
 
I had heard the J, U, an O are all the same heads, and depending on the cavity the heads were cast in depended on where the letters were "interrupted" meaning the spark plug holes were machined over the letters. They were all suppose to be O and parts of the letter was machined off.
 
were sm bolt (blue) 5 1/2" and large bolt (yellow) 6"...or were some large bolt 14's also 5 1/2"?
 
Uhhh X for defective ?? Buy a Big Block !!!.... JK...Just Kidding...:lol:
 
Most markings on parts are used for tracking... In case any problems come up, they can be used to trace it back...
 
In LA, around 1979, there was another X Head...
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I have posted pics of my early build 68 Formula S 340 heads here in the past. My heads are X heads without the X.

The casting number under the valvecover doesn't lie. So this story is completely believable.
 
X castings on automotive parts have always caused people to get excited thinkin "experimental" or "special" or whatever......and that crosses over to pretty much all makes. Chevy had the 041X heads. Ford has numerous X casting blocks. Lotsa Ford morons think an X Cleveland block is the shizzel. It's not. My Cleveland has not one single X anywhere and is a factory M code 4 barrel engine. My 351M has like six X's in the intake valley and so does my 400 block. Pontiacs had the 6X head........which was one of the worst for performance. Really, it's much ado about nuthin.
 
That's why my dads friend laughed about it. The guy advertised his barracuda had x heads and he knew why
But I get it. The X is easy to identify as being the correct head. My 70 dart has J heads and I thought at first that was wrong. I told my dad I'd take him to nationals set up a booth and put a sign up saying. Meet the guy responsible for the X head. Like he's Tom Hoover or something. Lol.
 
I believe the O,J and U theory too as you can tell the spark plug cavity seems to cut all these letters up pretty good. And to use similar O U and J to differentiate a head from a distance? No chance...they would use real oddball letters like V, Z and B that cant be mistaken. Now, tell me about the Z head....
 
ir3333 said:
O.K....how did they come up with 894...915...587...302...
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There's a group that pulls and assigns part numbers... each engineer goes to them to determine the new part number...

Those are just the numbers that were next in line when that respective engineer needed to pull a new number...
 
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