71 block in a 72 duster. Did this happen at the assembly plant

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SLOPAR72

SLOPAR72

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So my Pop's and I are going over a couple of projects for the car and I elected to pull the current motor and take the original which was pulled in the mid 80's and put it back in the car until next year. For whatever reason he looked at the date on the block and it says 1971. He is about to freak out lol... I can't get down there to check things out due to my work schedule however who has had this happen? He said the block has 11/71 on it.. Any info is appreciated...

Thanks,
JW
 
By the time November 1971 came along, they were full swing into the 1972 car builds so yes this is normal. I don't know the exact date (someone else on FABO probably does though). August / September is when you can expect next years car models to hit the showroom. If this engine was in a 1971 I would say it was a transplant.

Someone once told me the factories shut down for awhile in July to re-tool for the next years models???
 
That's nothing unusual. Parts are cast before assembly and '72 car production/assembly actually started in late '71. Restorers look for date codes for parts that are earlier than the date of car assembly. But there are occasions where Mopar used leftover parts from the previous model year. So it would be interesting to see if it had the earlier high compression pistons and/or 2.02 heads instead of the lower compression & 1.88" intake valves.
 
typopup said:
By the time November 1971 came along, they were full swing into the 1972 car builds so yes this is normal. I don't know the exact date (someone else on FABO probably does though). August / September is when you can expect next years car models to hit the showroom. If this engine was in a 1971 I would say it was a transplant.

Someone once told me the factories shut down for awhile in July to re-tool for the next years models???
Click to expand...

The car when he bought it off the lot in 1980 or so was about as original as one could get..... I need to check it out this weekend but if it ain't original to the car my pop's will be on suicide watch lol....

JW
 
SLOPAR72 said:
So my Pop's and I are going over a couple of projects for the car and I elected to pull the current motor and take the original which was pulled in the mid 80's and put it back in the car until next year. For whatever reason he looked at the date on the block and it says 1971. He is about to freak out lol... I can't get down there to check things out due to my work schedule however who has had this happen? He said the block has 11/71 on it.. Any info is appreciated...


Thanks,
JW
Click to expand...

A 71/72 should have a partial VIN stamp on the engine/ trans, so you should be able to justify each of them to the car. This is known as "matching numbers."
 
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The 1972 model year ran from some time in July 1971 into August of 1972, so '71 parts are quite common.
 
My '73 Dart Sport had a '72 trans and rear end. The 340 block was cast 11-25-72 and would have been in a '73 model year car.

Model years and casting dates are different a lot of the time.
 
You would have to understand my pop's when I say he was devastated yesterday lol. Talk about first world problems.... Having the original drivetrain to the car just gives him something to talk about....

Thanks,
JW
 
There is a partial vin number stamped on the side of the block on the passenger side by the oil pan, towards the front of the engine, this will confirm original or not.
 
I'd be willing to take that hodgepodge pile of parts off your pops hands for him.
We don't want him losing sleep or creating high blood pressure over it or anything, now do we.
Of course, it's not worth much of anything like that.
 
RogerRamRod said:
I'd be willing to take that hodgepodge pile of parts off your pops hands for him.
We don't want him losing sleep or creating high blood pressure over it or anything, now do we.
Of course, it's not worth much of anything like that.
Click to expand...


Lol.... As I said a first world problem....

JW
 
They launch the new model year in June/July the year before, so a November 71 block in a 72 is normal, that could be your original engine... Check the numbers with your VIN to see if it's the original block.

Here's a thread on how to decode the block info:

How to ID a Small Block Engine Block:
 
The 340 im putting in my dart came from a 72 Challenger Rallye. Completely rusted out car but otherwise all original and unmolested. It had a numbers matching block and was cast in Jan 1971.
 
My 76 dart had drum brakes all around yet Jan 76 it was mandatory for all vehicles to be discs. Check the date of build. Mine was built in the last month's months of 75.
Totally normal
 
Generally speaking, the engine would be built before the actual build date of the car itself.
That goes for most if not all of the other components that goes into a new car.
If you think about it, it only makes sense that it is that way.
The parts to build the car are assembled ahead of time so when the car goes down the production line, the workers see what parts are called for on the build sheet and then they are picked and ready at each station that the car stops at while being built.
For example, if a car calls for a 340 and a four speed, it goes right past the slant six and automatic station.
There will be several assembled engines with transmissions already bolted together and on a k-member so it can be slipped into the car as it passes along the assembly stations.
The engines, transmissions, and other items in the assembly need to be joined together and form sub units.
The blocks are cast (which the date is cast into the block at that time) and then it needs to be cleaned, machined, and assembled. Then it is sent to the factory to have other components bolted onto it such as transmissions, accessories, mounts, etc.
Then when the car is ordered, they assign a ''scheduled production date'' to the car.
The actual build date may vary depending on availability of all of the components needed to actually complete the car.
It may be delayed because say 340 4 speed air conditioned engines with manual steering assemblies have been delayed for 3 weeks.
They will then build the car when they know that the parts are in house, other than a few small items that could be changed on the fly if need be to push the car through.
The general rule is about 2 months from when the block was cast until it is finally assembled and ready to go into a car.
It's not unusual to see 6 months or even a week ahead of actual build date for some castings and components.
Then there are substitutions and discontinuation of certain items that factor into this scenario as well as using up of older stock to just get rid of it.
As the car is assembled, then they stamp the serial numbers into the pads to make it ''matching numbers''.

So, in summary, any car built for say the '72 model year that is built between August and December 31st of '71 will have date codes and casting dates in '71.
Anything built after that could have both or '72 dates on it, depending on how close the supplier cuts it to replenish the parts bins.

I hope this explains a few things............
Good luck,
Tom.
 
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