This was in a parts car I picked up recently.
71 340
- Thread starter RAT ROD AL
- Start date
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Al,
Did you show that punch marking recently in another post?
I could sware I saw it recently, the double punched looks so familiar
Did you show that punch marking recently in another post?
I could sware I saw it recently, the double punched looks so familiar
No sir, first post. I just took the the pic today
Al, if I read the stamped VIN correctly, I believe that's for a 72 model year, since it begins with a 2. That's a pretty dang early cast block for a next year model.
January 20 1971 must be for mid year or end of 1971 production.
I always thought that change came about about April 1971, but boy this sure disproves that, doesn't it?
DM sent
Tommy
Tommy
Is the 6 behind the 340 any significance ?
Cuda416
Well-Known Member
I believe it denotes the number of "repairs" made to the casting core. Over time, they'd fix them and up the number.
NC Engine Builder
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Correct. Generally speaking, the lower the number the more desirable. 340-1 is more sought after than 340-10 ect. But I've used them all with success
Bennoel 10
Well-Known Member
I was lead to believe the 340-"6" just indicates the "box" or core casting mold it originated from. They had more than one mold which the raw blocks came from. Then if an issue arose, it could be identified and corrected instead of checking all blocks. Can't imagine manufacturing one block at a time. Multiple pours at once. Wasn't there so maybe I'm wrong, just my understanding.
Cuda416
Well-Known Member
Nver said it was one block at a time.
Bennoel 10
Well-Known Member
And I never said you did. Sorry if i offended you, not my intention. I just stated that many ( more than one) were poured at once and this was just a way to identify which casting block the block In question originated from.
Cuda416
Well-Known Member
Not offended at all but if you're going to disagree, please offer some documentation so if I'm wrong, I'll learn something.
It's "my" understanding the number indicates what version the master core was at. You can only use them for so long before they become damaged and require repair. They don't replace the whole thing, they replace parts and increment the number to denote the iteration of the master.
Bennoel 10
Well-Known Member
Glad to hear you're not offended.
I started out saying " I'm lead to believe " and trying to explain what I was told. That said it appears to me that we're agreeing on the same thing. It was a way of identifying where, when, witch "box" the particular block originated from. I agree with your suggestion / explanation. Makes sense. I also originally stated "I wasn't there so maybe I'm wrong but that was my understanding " and no, I don't have any documentation just something I believe I picked up along the way.
4spdragtop
Well-Known Member
Cuda416
Well-Known Member
I would love to have someone corroborate this claim. Seems feasible.
340 casting "revision numbers" check in
340 casting "revision numbers" check in
Bennoel 10
Well-Known Member
Just read the thread, lots to retain and I will try and keep things straight in this old brain of mine. Thanks for the link Steve.
I ain't sure I go along with all that. Think of this. As they used a mold, they would naturally make small changes and improvements over time, wouldn't you think? I'm not sure if a low number or high number is necessarily better, but maybe a number somewhere in the middle might be. Of course the higher number, the more "wear" the molds might be seeing. But I think a middle number might mean a good one. Just more thinkin that probably means nothing. LOL
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I dont really know, just what I've heard for years. But like I said, I've used all various blocks without issues.
I've heard the same. I have to think there was more than one mold and this is how they tracked them. Mold # 6 has too much core shift. We need to fix that one.
dr dodge
Well-Known Member
think of the amount of blocks per day
the "casting row theory" makes lots of sense
#1 v #8 coldest pour
and it's not "a mold" it's a mold making process.
and a massive hot pot and a crap load of precision sand
how they did that was amazing
the "casting row theory" makes lots of sense
#1 v #8 coldest pour
and it's not "a mold" it's a mold making process.
and a massive hot pot and a crap load of precision sand
how they did that was amazing
Yeah it is. You just have to have a mold to make a mold. lol
dr dodge
Well-Known Member
it was amazing mopar, gm, ford were all slinging cast, lots of it
heads, rear axles, and everything else
imaging as an independent foundry how do you track that?
were fords cast after the mopars? heads after blocks?
all this history we don't know, and never asked the guys that worked there.
this is how in real time history disappears at our fingertips
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