Crate hemi casting numbers

Here's a casting number with insignias...what's it really mean? The triangular sign with "MC" in it...and the "2L20"...

Motor Castings. don’t know what the numbers signify.
Motor Castings has a building here in West Allis WI. I believe they have been bought up and shut down within the last year or two.

Mopar Mega block, pre-world

Full water jacket mega block. The siamese block has Mopar cast in the block above number. MC- Motor Castings .Zippy has never been able to get anyone to disclose the other numbers.

My Hemi block has the same similar numbers.

Yep, what they said.

2L20 had to have been something internal at the Motor Castings foundry.

Best as I've been able to research, Cummins/MP did not track that particular number and it had no important meaning to either entity.

I always thought it ridiculous that all the hard information was contained on the yellow Cummins decal.
Once the decal was removed, the info was lost.....But that's how they ran it, it was definitely not the only ridiculous detail,
and over time you just shake your head and try to work with it as best you can.

2008 was the changeover year to the more beastly P5153843 casting, when the foundry moved to Dalton (Backwards DF marking) and Machine work moved to
Royal Oak Boring/Royal Oak Industries.

Yep they're the same numbers. The pictures are Hemi blocks.