Earliest 340 production date/number

Saw a picture of the side of a guy's 340 on another site, thought it looked very close, if not the same date, as my older 340 (I have two, the younger one is from '69). Went and snapped a shot to show him- mine is two months earlier exactly. His is 8/22/67, mine is 6/22/67

Both are pretty early in the 340 production. Any ideas of when 340 production actually started?

And, yes, I am going to stuff this motor in a car. I have an '85 AHB Plymouth cop car that would be loads more fun with a warmed-over 340 in it as opposed to a smogger 318, 4-bbl.(which weirdly has a "Premium Recommended" sticker on the inside of the fuel door).

Typically the model year launch is somewhere in the end of June and early July. They stagger the launches so the engineers can support more than one launch if necessary.

Now to meet the launch at the assembly plant, they would have to build the engines a little bit earlier. Your block may have been in the first month of production. they would need time to cast the block, then send it to the engine plant, machine the blocks, assemble the engines, put a few of the first ones on dynos to test them,. and then send some to the assembly plant for launch.

Keep in mind, that the engine block machine line has to be "certified" before being able to send any parts through. Each station has to run parts, and measure them, and then calculate if the process is "capable". This means that it can stay within it's tolerance. They would have to send at least 30 parts through and measure them to establish capability.

The bores have to be measured for surface finish to make sure that it is within spec. This takes alot of time. I was involved in launching a new hone on a block and it took tons of measuring. The bores have to be measured for size every 45° at 10 levels throughout the bore. Then you have to do "traces" on the bores for surface finish to make sure that they are not too smooth or too rough, and can maintain those dimensions.

After the line gets certified, then they run a batch of blocks, and then assemble them into engines. They will test a few engines for a "quick" test on the dynos at the engine plant, and then send some to Highand Park for design engineering to put on "long term" dynos to verify that they are good.

This line certification is usually run before launch. They call it a "pilot build" and they do one 6 weeks before launch, called PVP (pre-volume production) pilot build in May. This is where they would certify the machine lines and get parts testing. Then they launch during the end of June/early July.

Then the engines are sent to the assembly plants to be built into cars. The design engineers are usually present for the first few cars to be "walked" down the line station by station, and helping the assembly operators get familiar with the new designs. Once they get the hang of it, then they start speeding up the line until they reach production volumes.

Your engine may have been run in the early stages of launch.

Thanks, Kuda. I know model year production wraps in June/July of the calendar year, then the next calendar year model production starts up in July/August.

V-100 said:

Thanks, Kuda. I know model year production wraps in June/July of the calendar year, then the next calendar year model production starts up in July/August.

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They ramp down in early June, and start up by mid July.

Like I said earlier, they purposefully do not launch all plants at the same time, they stagger them so the design engineers can support more than one launch if needed. But they pretty much get the new lines running between mid June and mid July. Then ramp up the line speed gradually as the operators get more familiar with the new changes.

If it's a brand new vehicle, they have been known to hold them for a month while they complete evaluating them to make sure that they are good enough to ship to customers. Then you see them in Aug.


The first few vehicles are sent to design engineering and the proving grounds so they can be evaluated for any problems before sending them to customers.

They also get the first few engines from the engine plant and put them on dynos to make sure that they will hold together.

Mine is 6/21/67, just one day older.

I have an original 1968 Barracuda Formula S 340 car. The date code on the block is 6/19/67. I also have a 5/67 340 engine block. The earliest date code I have seen is a 4/67.

This is what I love about this site- all kinds of info!

I just purchased a 5/25/67 340 block

I was told that the very first A-body to carry or be carried by a 340 was a 67 Barracuda. That was on test grounds, spring of 67. He also said Plymouth dealerships received 340 S Barracudas before Dodge dealerships received 340 Darts.
This guy was a highly achieved master tech from a Dodge dealership in Cleveland Ohio. He liked to spout trivia, bring out old service bulletins, and such.
If he stated why they chose a Plymouth instead of a Dodge I don't remember ( was years ago ). Maybe location was a factor. We know Plymouth moved on to 318 and 340 while Dodge used up the remaining 273 engines lasting into early 69.

The earliest for me was a 2-67 and it had a couple of things that I've never seen before..it had a serial number on the drivers front of the block 00007 and it had one machined pocket on both deck surfaces that told you the deck height when you dropped a dial gauge into it..

Rob R said:

The earliest for me was a 2-67 and it had a couple of things that I've never seen before..it had a serial number on the drivers front of the block 00007 and it had one machined pocket on both deck surfaces that told you the deck height when you dropped a dial gauge into it..

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Now that is early.... Never seen one cast that early. Would stand to reason. 68 model cars were probably released around june or so of 67? usually blocks were cast 2-3 mo. before vehicle production date, maybe sooner being a brand new engine at the time

Rob R said:

The earliest for me was a 2-67 and it had a couple of things that I've never seen before..it had a serial number on the drivers front of the block 00007 and it had one machined pocket on both deck surfaces that told you the deck height when you dropped a dial gauge into it..

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Being that it was so early, and with a low number, it would have been part of a "pilot" build. There is one about 6 months before production launch. It is used to see how well the tooling is and how everything fits/works together. That could have been one of the first batch of blocks to come off of the production 340 block casting tools. May or may not have been machined in the engine plant, or in a prototype machine shop. It could have been in the first batch of blocks run to test the block line's capability to machine them and set up the process limits/targets.

That's cool that you have one of that vintage!

mine was april 22 67...august 28 built car

ph23vo said:

mine was april 22 67...august 28 built car

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Very possible. They would want to build up a "bank" of engines a few months ahead of the car plant launch.

Then they would have time to dyno test a few to make sure that they meet up to standards and are good enough to send to customers. They would not let the engines go into production until they completed some dyno testing. This testing could take 2-4 weeks to complete on a dyno.

I'm sure that they had some engines from the first batch of the build before production that were on dynos at Highland Park within a week of when the engines were built.

They would also have the blocks cast and then run them through the engine block line before the launch.

Then maybe sit for a few weeks until they were run down the engine assembly line. Then have a batch of them ready to support the launch at the car assembly plants. I'm sure they only put them in cars that were built at one plant before the rest started. All the design engineers would have been there to make sure that their parts were not having any problems, and address any problems that may come up, and show the production operators how they go together.

I knew it'd pay off to search for this thread instead of start a new one!Anyways,I was digging around through some of the blocks I still have and found a 340 dated 6/21/67.After reading these posts I realize it's not exactly rare to find one this early,but I couldn't find a VIN stamped into it anywhere.Not even a machined pad to stamp the numbers into.It makes me wonder if this was a factory replacement block or something along those lines.Anyone have any ideas on this?

early 68 340 blocks had no vin stamping, if it did, it is behind the driver side head where the transmission bell housing bolts up. My 68 dart has no vin either

Casting Date: 6-22-67
Engine Assembly Date: 9-22-67
Car Build Date: 10-02-67

Vin behind left head.