3970010 blocks with December "M" in casting date

[cib12]

Does anyone have and info on the "M" (Dec) casting date on the 010 block.It is in Colvin's Chevrolet by the numbers. Does any one know more about this. My Z-28 has this. Thank you for any response on this.

[Kurt S]

Of course.
Very detailed info about M blocks at:
http://www.camaros.org/drivetrain.shtml#BlockCast
And it wasn't a code for December!

[cib12]

thanks very much to clear this up for me. would you have a pic to see how it should look thanks again

[BARRY]

HI yes dec 1970

[Mr70]

From CRG:
"M"-Coded Blocks
"There is one exception to the normal block casting date convention that has been observed: some blocks have been seen with "M" cast codes. Research by the Saginaw Metal Casting Operations of GM Powertrain Division has found that these "M" codes are not date codes, but actually a foundry code used to indentify parts that were made to evaluate a casting process change. After evaluating the parts, the blocks would either be destroyed or released into production. There is no way to determine the date an "M"-coded block was poured".

[cib12]

thanks again for your response Kurt S- could you give me an example of what the m code might look like--is it a m only or could it be (example) m 4 7 or something similar to that thanks again

[70 Forest Green Zee]

As far as I know "L" has always been the date code used for December....example:

[Kurt S]

[ QUOTE ]
could you give me an example of what the m code might look like--is it a m only or could it be (example) m 4 7 or something similar to that thanks again

[/ QUOTE ]
It would be M and a 1 or 2 digit #.

[cib12]

thank you Kurt