Letter E on s14 block

[BillBrasky]

I was cleaning up an s14 that I bought a few weeks ago and I noticed that it has a letter E painted on the outside of the block at the front of the engine on the intake side. It's not on my engine that I just pulled from the car and I can't find any mention of it over on s14.net. Has anyone seen this before or know what it means?

[Robert]

it means, expensive.

[Farbin Kaiber]

It's the elusive m3 eta.

[89AlpineM3]

Its on most blocks, mine has it. "Jake" told me it was just a stamp by the company that made the blocks