In 1956, both the engine and vehicle serial/sequence number were treated the same way. You subtract 1000 from the unit number to obtain the sequence/serial number.

I do not think that anyone has posted GM/Chevrolet documentation that states that GM placed any codes on the chassis in 1956. Some states (and some peope) might have placed a code on the chassis.

Where is your chassis code located; and, what is the code?

May red58 (Bill), or someone else, will post information here. I think there was a recent discussion on chassis codes?