Hemi block stamp

[Robertop]

Guys: my Hemi engine, 69 roadrunner, has a stamp on the bottom pad that starts with "RM 426, etc, etc,". Does anyone know what the letters "RM " mean? Thank you.

 

[R/T Boy 67]

It should be the engine assembly plant, which would be marysville for the 426 hemi. I have seen different codes, such as MN and NM, but all 426 hemis were built in that one plant.

 

[Robertop]

It should be the engine assembly plant, which would be marysville for the 426 hemi. I have seen different codes, such as MN and NM, but all 426 hemis were built in that one plant.

Thank you!

 

[33 IMP]

RM also indicates a road runner, as in RM23H9Gxxxxxx (st Louis built 69 383 hardtop, for example)
Early 69 had the full Vin on the pad just above the oil pan, later in 69 you would find
9Gxxxxxx for the above example.

 

[AR67GTX]

Bottom pan rail stamping on my 68 built Hemi.

I think it’s the assembly date on the 10,000 day calendar and the position in the assembly numbers for that day. Maybe something else I’ve forgotten.

 

[33 IMP]

I'm pretty sure 68s and 69s would have different info.

 

[dadsbee]

OP needs to break out the camera...