#3418915 'J-Head'
Can you see the slight difference in Port Configuaron.
Can you see the slight difference in Port Configuaron.
X-heads vs J-heads: what's the difference??
- Thread starter RzeroB
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Hey Snake,
You don't think you were the 'First' to port out Goldie do you........
That Odometer had spun around the 'Dial' a few times before you got there.
Goldie Hawn >
"I always go with the 'X-Heads'. Stock vs. Stock, they have proven to be more responsive
than the 'J-Heads' during the high RPM's at the Track."
You don't think you were the 'First' to port out Goldie do you........
That Odometer had spun around the 'Dial' a few times before you got there.
Goldie Hawn >
"I always go with the 'X-Heads'. Stock vs. Stock, they have proven to be more responsive
than the 'J-Heads' during the high RPM's at the Track."
I always felt it 'odd' that 'Maggie' turned down Snake in
'Escape From New York'.
Maybe she liked the 'J-Head' over the 'Snake'
Look Snake,
I'm telling you, Maggie and me are just friends. There is no funny business going on.
And as 'The Brain', I know what goes best on the 340.
It's the 'X-Head'. Trust me Snake.
I'm telling you, Maggie and me are just friends. There is no funny business going on.
And as 'The Brain', I know what goes best on the 340.
It's the 'X-Head'. Trust me Snake.
Swinger 340
Well-Known Member
If the valves were receding, wouldn't that give you a larger CC? Maybe it is time for a valve job. If so, I would have installed harden seats on the exhaust. Not sure 100%,but I believe the "J" heads were a 360 head, used on the early 360 2bbl. Some were machine for the 70' 340 6-pac., with angel push rods. I don't recall any were used on the 340 4bbl (X,O and U, were a 340 head).
PRH
Well-Known Member
I have refurbished/reworked numerous 915 heads that came from the factory with 2.02 intake valves.
The most recent set just a few weeks ago.
Untouched from the original 71 340 out of a Duster.
The most recent set just a few weeks ago.
Untouched from the original 71 340 out of a Duster.
Dartswinger70
Well-Known Member
The late smogger 340 had J's with 1.88s which could then be punched out to 2.02 and milled to reduce some of that large combustion chamber ,some say they could be as large as 72 cc's. >
furrystump
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This car runs 10.3’s with J’s and a thermoquad and I run 11.3’s with X’s and the difference is not the castings.
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Dartswinger70
Well-Known Member
In my mind really The Xand Js should flow similar stock, teh Js had bigger combustion chambers 72 cc's Xs were smaller 63 -65 CC'sbu t thats hearsay. One would have to measure. However the trick was back in the day as I understand it. to mill the Js and put 2.02's in them.
ir3333
Well-Known Member
If you guys consider X or J heads 40 year old junk....what do you think about the cars themselves?
You guys might be in the wrong hobby if you don't enjoy these old cars and their parts?
You guys might be in the wrong hobby if you don't enjoy these old cars and their parts?
furrystump
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Honestly, if I didn’t have to run a stock casting, I would run the best aluminum head you can get.
Dartswinger70
Well-Known Member
Stock cast heads are fine if they work... on a street car, not everyone is drag racing. Besides they ran the stock stuff in the 70s and 80s and did rather well with it.
. P.S. dont want the Js or Xs let us know here... someone will buy em.
. P.S. dont want the Js or Xs let us know here... someone will buy em.
Not that stock heads suck but cost wise it's hard to argue spending money on them isn't the most cost effective solution. And I don't buy some don't care about performance at all, or otherwise most modern family cars wouldn't make the power they do, embarrassing most older performance cars. Even a slant six has over twice the power needed to be able to drive around, technically making it a performance engine.
Oh,
You mean the $6 Per Hour Engine Assemblers at the Chrysler Mound Road Engine Plant in Detroit.
Do you really think that anybody cared which Head went where on Friday afternoon in 1970......
Friday Night in Detroit at the Chrysler Engine Plant.........'This Bud's For You Crackedback'
The heads come to the assembly line on a pallet... The workers just unload them and install them as they come, no coordination from one side of the line to the other...
Dartswinger70
Well-Known Member
6 bucks an hour in 69-70 was admirable the new 340 dart was 2800-3200 bucks depending on options
Swinger 340
Well-Known Member
I
I always heard, "never buy a car built on a Monday or Friday". That would mean 40% of cars could be a little off.
Dartswinger70
Well-Known Member
Well as humans we make mistakes. I know a guy who bought a new 2001 Ford Ranger with the 4 L SOHC engine. It was 4X4 nice little truck. He had it a while and the trans acted up check engine light etc. It was still under warranty ,he took it in, they told him it had a part missing inside the trans from the factory, I forget whaT IT WAS BUT IT WAS LIKE wHA? ITS AMAZING IT RAN FOR A WHILE BEFORE ACTING UP...sorry caps lock
No, what about you??? Is your ability to do your job any different than any other day???
There is just as much chance of them screwing it up Tue - Thur as on Monday and Friday, just like you on your job...
In a typical union plant, each worker gets their job as they bid on it and the highest seniority gets first pick...
The worker who gets that job does it every day, every week, all year long... They develop a rhythm doing that same part over and over... By doing it so many times they find out the most efficient way to get the job done...
Periodically they miss a day, whether it be a vacation day or sick day or any special circumstance that comes up and they can't make it to work that day (ie. Mondays after holidays or long weekends)... The assembly lines are divided up in sections, each section has its own supervisor... That supervisor has to figure out who is absent/missing and get every job covered for when the assembly line starts moving... And the line does not wait...
Now the supervisor has to put a substitute in that job and show them how to perform that particular operation... And has to do it for every person absent in their section... Now what if there are about 5 - 7 people absent in his section??? That supervisor is busier than a one-legged man in an *** kicking contest to get their section of the line ready for start-up...
If the line starts up before that job is covered and that part is missing, it goes in the repair station at the end of each section and the dedicated repairman for that section will fix it and send it along its way...
Now those substitute people are not used to doing that job and have to work through the learning curve to develop a rhythm for that job to keep up and do it properly... After a while they get the hang of it and things run smoothly, let's just say anywhere from 15 to 45 minutes...
So the better generalization would be to say, don't buy a car made on a day when there is high absenteeism....
Better yet, don't buy the early or end production cars... Mostly the end of the year or model cars...
The first launch cars may have some substitute parts or early prototype parts... The early prototype parts are not so bad as they are to the blueprint for that part, just not made off the production hard tooling, they are made from the soft tooling that made the initial parts for testing to prove them out before production... If the production hard tool is not ready at launch time they will write a temporary substitution for that part to use the soft tool part from the prototype stage that meets the part print until the regular production hard tool is ready and certified... Nothing wrong with that because they make the part the same, but the soft tool wears out faster than the hard tool and is limited on how many parts it is capable of making before wearing out, that's why they have production hard tooling - to handle the long term run for that part...
Now the last one of that model year is the higher risk... At the end of the year as production is ramping down, they may not have as many of that particular part left in stock at the assembly plant... A good example is a fastener (screw or clip)... If that particular part is being phased out and now becoming obsolete for the next year, they may be running short of them in the last week of production... The assembly plant has standard quantities that they order at a time, and if they only need a small portion of the standard quantity, they are not going to order a full order and be left with a bunch of obsolete parts and have to scrap them and eat the cost...
In this case they will look for a substitute part (screw) that will fit the 'hole' and do the job... It can be as simple as a different coating, or slightly longer or shorter, but will still do the job... The design engineer will approve the substitute part and the manufacturing engineer in the assembly plant will write a temporary substitution to authorize using the other part in its place... There is a fastener database listing all of the available fasteners used by the company on all products... They will try to find one that is used in that same assembly plant as it is already in stock, they just have to increase the usage in the database so they don't run out of that one... Second choice is to find one that is used in another 'sister' assembly plant and the production control guys for the plant in need will call the plant that has enough to share and have them ship them to the plant in need... The production control guys have a database and can look at the inventory in all of the other plants to see if they have enough quantity to share...
So it's the last ones off the assembly line that have the higher risk of not being built to the original design and may not be as good as the standard production ones... And us as public are not privy to that information.. Tha's why there's a statement in most of the brochures that the product specifications may change at the manufacturer's discretion...
However the fastener substitution can happen at any time in production if the assembly plant runs short of a particular fastener and has to find a substitute to get by until they can get another batch from the regular supplier.... It could be because someone in production control missed it was running out and did not order it in time, or the supplier is short and can't make anymore before the assembly plant runs out...
They do this because they don't shut down the assembly line if it's not necessary... A typical assembly plant runs about 70 cars per hour average... If the line stops for one minute that is one less car they have to sell... Think of how much money that car lists for, and how much money is lost PER MINUTE the assembly line is stopped... If the line is stopped for a half hour...
Back in the mid 90's if the supplier was responsible for stopping the assembly line they were charged $7000 per minute it was stopped!!! This was to cover the lost product and paying the crew of assembly line workers to stand around waiting for the line to start again... If you are the reason the assembly line stops and they loose thousands of dollars, your *** will be on fire answering to the higher ups or thrown out the door...
Dartswinger70
Well-Known Member
Is it the individual worker these days or foolish engineers who are at fault? Who knows...
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