010 Block Date code

[muscle joe]

HAs anyway run into a 010 Block that does not have a casting date on it, I mean it is not there, I have removed the hood and got on top of the engine and used the best lightening, and believe me with that scenarion I would not miss it and it is not there, behind the flange on the right side behind the head, 2 little screw indentations to hold the plate onto the form, I know what I am looking for and I tell you it is not there, there is no grinding in the area at all either, just the regular rought texture you would expect, I am thinking as in some of the quality control that went on that at the start of shift someone forgot to screw the date plate on for the date casting and it went unnoticed for a little bit   weird   Joe

[flyingskibiker]

Didn't they leave off dates on "test" casts of new design blocks, heads, etc.

[Indy 69]

Didn't they leave off dates on "test" casts of new design blocks, heads, etc.

Are you referring to these blocks?
"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.
   

[muscle joe]

Where would you look for the M designation

[JohnZ]

If the brass date code tag (see photo below) was left off the pattern, the recess for it in the pattern would show up as a recess in the casting; is there still a stamping on the front pad on the block?

The "M" blocks just had an "M" where the casting date tag was normally seen.

[muscle joe]

John you have all the toys, no, no recess in area either, very confusing, yes there is a front pad stamp, I have just bought a 837 and am going to install   will get a pic of front pad stamp and send, pad is stamped VO515DZ, pretty much lines up with vin 654429 and other eng  dates   

[tmodel66]

I used to be a molder in a grey iron foundry. There were 2 ways of placing I.D. stamps. They were screwed directly to the pattern or screwed into a recess in the pattern. I don't want to be a smarty pants but if the tag was left off it would be smooth where the date should be or have a raised block where the date would have been because iron would fill the void.

[JohnZ]

if the tag was left off it would be smooth where the date should be or have a raised block where the date would have been because iron would fill the void.

An open recess in the pattern would create a raised area in the sand mold, which would result in an identical recess in the casting.

[McKenzieDave]

M-Code

[McKenzieDave]

By the way, that M-Code block is from a very early '69--386 block.  What is funny is that a very early car is VIN stamped by the oil filter.