340 Casting Number Questions

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66Baccaruda

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I've got a couple of 340 blocks that I just acquired. One of them is cast date in 69. I can't remember the actual date. The casting number is 2780930 and 340-3. The other one has a casting date of 7-7-70 and 340-5. Does anyone know what the -3 and -5 stand for? Back in my auto parts days if I remember on a 318 the automotive casting was a -1 and the motor home and truck block was a -2 or a -3. It seems to me the 360 was the same. Things are a bit fuzzy after this many years.
the other questions deal with heads. I have two sets, one of which is supposed to be the original off the Duster. They are 915 J heads. Some references say the 915s were 72-up 340 and 360 1.88s while the 71 340s had a different casting. Two of the heads that came with the blocks I got are cast J but backwards and one is an X and one is a O. I didn't get the casting number off any of these, just the letter. What is the difference between the J, X, and O? Any help is appreciated. Thanks.

Emil
 
I was ware that the 3 and 5 were the core bins numbered 1 to 5.Here's what my Chrysler Corporation Part and casting numbers book says:

casting #3418915- 1970-71 360 open chamber 1.88, 1.6 (J,Z,O)

casting #3418915- 1970 340 T/A open chamber 2.02, 1.6 (O, U)

casting #3418915- 1971-72 340/360 open chamber 1.88, 1.6 (J)
 
915 heads are 70-72 340/360 and either 1.88 or 2.02 intake valve sizing

O head is the same as the 915 head

X head is an 894 casting with 2.02 valves used from 68-70.
 
The 3 and 5 to my understanding is the revisions or core that the block was pored into. 3 maybe was fine for a time then cracked and eather was repaired or replaced at the time of repair or replacement it would go to 4 ect..
 
Hi Guys,
Thanks for the casting number info.
Am I crazy or just going senile that the 318-2 and 360-2 were truck blocks? It's just bugging me, no real need.

Emil
 
Thx Added '66Barracuda, great topic !

& --- EL5DEMON340--- WITH RESPECTS, not an casting reference, molds are typically
broken down after the ' casting clock ' reaches '10'... (I have seen 12-14, beancounter dependant lol)...

- # after the 7 digit casting number is a tooling update :D

READ HERE HONORED POSTERS
 
They also need to put cavity numbers on the castings in case there is a quality problem they can trace it down...
 
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