340 Engine Cast Question

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Divenut

Divenut

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Hi Folks,

Got the Duster up on stands today, and pulled some number off my 340, i.e. 2780930-340-1. Anyone know what the "1" indicates? Also, there is no date cast above these number. Any other way to date the motor?

Thanks as always,
Pat
 
Date will be on the pass (other) side.
From what i've learned the -dash- # indicates the # of castings or revisions that particular mold has made.
-1 would be the first -2 the second so on.
 
The 1 stands for the zinc percentage in the block I believe. As for dating the block...there should be a small stamping on the front of the block right under where the head lies on the block. Should give you cubic inch and 2 digit year (71 for example)
 
I'm pretty sure the dash and last # indicates the sand casting mold revision/repair. Same would apply to cylinder heads.

Casting date on the other side says it all, but you could get an approximate idea of the year by the balancer - cast (with counterweight) or forged (flat face) & a TQ would indicate '71 or newer - if it's all original to the engine.
 
74swingerlover said:
The 1 stands for the zinc percentage in the block I believe. As for dating the block...there should be a small stamping on the front of the block right under where the head lies on the block. Should give you cubic inch and 2 digit year (71 for example)
Click to expand...

Interesting, as i have seen dash #s as high as 27 on 318 blocks, shouldnt ever rust that way.
My 72-73 340s are -6 and 7
71 360 is -2
72 360 is -1.
Makes perfect sense
 
318's are pretty reliable.....

I heard it from some old guy when I was young. I haven't seen a block go over 8, so it made sense to me. But 27, I think you would be right on with casting sequence.

I wonder though how many 318 blocks would be made from a mold as they made tens of thousands a year. Must of gone through alot of molds. You would figure they would of found a way to make the molds last longer to save on costs
 
Dluvr: np, couldnt help myself!
They cast slants 2 at a time, crankcase to crankcase!
Now THAT would be a thread: "heard it from an old guy when i was young"....!!
 
Loco: didnt some 4sp cars get steel cranks later than 71? Just curious as im not 100% sure on that one.
 
Locomotion said:
I'm pretty sure the dash and last # indicates the sand casting mold revision/repair. Same would apply to cylinder heads.

Casting date on the other side says it all, but you could get an approximate idea of the year by the balancer - cast (with counterweight) or forged (flat face) & a TQ would indicate '71 or newer - if it's all original to the engine.
Click to expand...


as said...indicates the number of time the casting mold has been repair..or revised...
 
66V100 said:
Date will be on the pass (other) side.
From what i've learned the -dash- # indicates the # of castings or revisions that particular mold has made.
-1 would be the first -2 the second so on.
Click to expand...


Thanks 66V100...will check out the passenger side again. Very hard to see the block with the header in place. Need to dig out the old "mirror on a stick" to get up in there.

And thank you everyone else for the explaination of the "1".

You all rock!

Enjoy the rest of the weekend,
Pat
 
What part of that number or any that would show "numbers matching"?
 
locomotion is right on and no 1 is a very good block from what understand
 
Locomotion said:
Casting date on the other side says it all, but you could get an approximate idea of the year by the balancer - cast (with counterweight) or forged (flat face) & a TQ would indicate '71 or newer - if it's all original to the engine.
Click to expand...

Thanks Locomotion. Looks like the balancer was added sometime later, i.e. it is a "Direct Connection" piece.
 
66V100 said:
Interesting, as i have seen dash #s as high as 27 on 318 blocks, shouldnt ever rust that way.
My 72-73 340s are -6 and 7
71 360 is -2
72 360 is -1.
Makes perfect sense
Click to expand...

I have read here that the -# is the mold revision or rework cycle. Lower may indicate a better block due to less core shift. I have a 71 -1 360 block I was gonna use as the basis for a stroker.

The thinking is it may have less core shift and this thicker walls on the cyls.
 
Airwoofer: the 71-1 i have has virtually no core shift. It was a motor home block.
The 71-2 isnt as consistant. Has a few cyls that are very close, if not into the cam tunnel at the bottom.
I would say -almost- any of the 70-74 360 blocks would be the ideal ones to use for 4"+ stroke.(if one is to use a production block) For a few reasons. Better metal, main bolt threads are blind, i have read/heard they have the same cyl bore cores as 340s, so would basically be a big main underbored 340 if any truth to that. Will have to start a new thread bout early 60 blocks.
 
To correct myself the 72 moho 60 i have is a -1, very nice casting.
The 71-2 is the one with not so straight bores. (int to ex not front to back)
 
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