Intake Letter

[oneZ11]

I've noticed that 4 barrel intakes for small blocks have a letter stamp on them, as well as the usual casting/date codes, etc. What do those letters mean?

Q:  If I have a '69 350/300hp, with the correct intake, what would that letter be? (Early March motor date code).

[tmodel66]

Where is it stamped? I'll go look at mine but I don't remember it.

[Petes L48]

Stamped or cast?  I think the 67 intake had an R, it may be explained in the Colvin book.

[crobjones2]

If you're talking about the letter by the coolant neck, my e219 has an R