When were big blocks stamped?

[Tom L.]

I was told by someone, who I believe to be a reliable source, that the engine assembly date and broadcast code were stamped on big blocks after the heads were installed. I offered that information in response to a question in another forum and I was corrected by another forum member. The TIM is silent on the issue. Does anyone know when they were stamped? The context is whether a stamp under the head plug is suspicious? Thanks.

[Dick W.]

Re: When were big blocks stamped?

Big blocks were stamped before the head was installed, small blocks stamped after the heads installed

[Tom L.]

Thanks

Thank you for the clarification.