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1970 340 head casting numbers

  
Mopar Muscle
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1970 340 head casting numbers

 
340moparman 340moparman
New User | Posts: 10 | Joined: 10/08
Posted: 10/09/08
09:07 AM

I have a 1970 Duster I'm doin over.I pulled the motor and pulled it apart to rebuild.I started going over casting #s.The block # is FW340P323290305.The heads # is 3418915E AAWJ360.According to my book the casting # for 1970 heads is 2531894.They have 2.02 intake and 1.60 exaust,with non-adjustable rocker arms.Do these casting numbers make any sence to any one?  

3404spdvaliant. 3404spdvaliant.
Guru | Posts: 771 | Joined: 12/07
Posted: 10/09/08
09:21 AM

71' &  up heads, and what's the date on the pass side of the block?
I'm about to buy a 70 4spd duster from a guy in so cal and the situations the same, 71 bottom end and j heads, orig motor missing but comes with extra 340 and at.
Somewhere down the line the motor was changed, I mean it couldn't have been so late production that it came with a 71' power train.
Now a early 71'production with some 70' 'parts' would seem more probable to me.  
age is no lock on brillance

mohead mohead
User | Posts: 81 | Joined: 03/08
Posted: 10/09/08
09:23 AM

Just measure an intake valve. if it`s 2.02 you got the good heads. if not, someone snagged the x heads, and you probably have 360 heads.  

3404spdvaliant. 3404spdvaliant.
Guru | Posts: 771 | Joined: 12/07
Posted: 10/09/08
09:34 AM

If there 915 there not x heads.
J heads came 2.02 also in 71'-72' 340's.  
age is no lock on brillance

340moparman 340moparman
New User | Posts: 10 | Joined: 10/08
Posted: 10/09/08
09:48 AM

The number on lower left-side of the block is 2780930-340-7 and yes it has 2.02 and 1.60 valves  

340moparman 340moparman
New User | Posts: 10 | Joined: 10/08
Posted: 10/09/08
10:42 AM

the date on the block is 1-3-70  

AdamR AdamR
User | Posts: 78 | Joined: 09/08
Posted: 10/09/08
05:05 PM

Is there a casting date on the heads ? I believe 915s were used in 70 also. The 202 valves were used from 68-71 and replaced by 188s in 72.

There should be a vin stamped in the block near the oil pan rail.  As for the heads, All LA 340-360 heads flow pretty much the same X,J,U,O doesnt matter. The big difference is valve size and on a street motor I wouldnt even worry about that all that much.  

3404spdvaliant. 3404spdvaliant.
Guru | Posts: 771 | Joined: 12/07
Posted: 10/10/08
08:34 AM

I have seen a 360 date coded 70' before and a 340 date coded 67'
But I've never seen j heads on a 70' 340 that weren't T/A heads, But you never know.....they did weird stuff depending on the factory.  
age is no lock on brillance

340moparman 340moparman
New User | Posts: 10 | Joined: 10/08
Posted: 10/10/08
02:28 PM

According t o my book (How To Rebuild Your Small-Block Mopar Engine)The #3418915 AAWJ 360 is a T/A head.But,they claim they will not work on a LA engine block.They said,they would bolt up but,would not work.When I purchased the car I drove it home.It seemed to run fine.How can I tell the difference between T/A heads to regular J heads?  

AdamR AdamR
User | Posts: 78 | Joined: 09/08
Posted: 10/10/08
04:55 PM

TA heads have offset rockers on the exhaust side. The bolt up and work fine on any LA block as long as you use the correct rockers and push rods.  

340moparman 340moparman
New User | Posts: 10 | Joined: 10/08
Posted: 10/10/08
05:09 PM

Hey, thanks for your info AdamR. It had non-adjustable rocker arms and i purchased roller rockers Cat aluminum rocker rollers and new push rods. When i purchased these, they did not specify for any specific head, so what is the correct rocker arms and push rods.  

340moparman 340moparman
New User | Posts: 10 | Joined: 10/08
Posted: 10/11/08
07:11 AM

Hey Adamr,I did find the vin # stamped on the oil pan rail.It's 0B383111.If this means anything to you,let me know.Thanks.  

JohnsDuster340 JohnsDuster340
New User | Posts: 1 | Joined: 11/07
Posted: 11/15/08
05:50 AM

I have a similar situation. I have a 1970 that has the original drivetrain.  

I pulled the valve covers and discovered that it has J heads (3418915B,3418915E). They do not have offset rockers.  

One of the heads is has a date code of 12049 and the other 12129.  I cannot confirm this but I believe that the date codes read 12-04-69 and 12-12-69 respectively.

If this is accurate, then both the x heads and j heads were available for 1970.  Wink  

3404spdvaliant. 3404spdvaliant.
Guru | Posts: 771 | Joined: 12/07
Posted: 11/15/08
08:49 AM

New flash, I got a hold of the orig 70' 340 motor and it also has j heads 2.02-1.60

The car I have is number 51 some odd thousand, so late production, hence the j heads
makes sense they had to run out of X's at some time.  
age is no lock on brillance

Bob70Challenger Bob70Challenger
User | Posts: 51 | Joined: 08/08
Posted: 11/18/08
04:22 PM

So I'm curious, my 340 has X heads with the X stamped clearly on the head in between the plugs. If J heads also have the 2.02/1.60 valves what's the deal with the X heads? Wouldn't they be exactly the same as the J ?  

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