Guys I got my forged 350 crank #1182 back from machine shop this summer, looked it over, coated it with LPS3 oil, bagged it up and secured it in it's vertical stand, (LPS3 turns waxy and keeps machined parts from ever rusting). I'm thinking about selling the entire rotating assembly to go 421 or 434 instead of the planned 377 build. I wanted to look it over close before deciding to list it or not. I noticed the front counterweight has an X marked on the rear of the weight. The 1182 marking is just on the other side. The large X looks like it was struck into it before the forging cooled down, you can see the tool mark as it recessed into the throw slightly around the X, like a square letter stamp was used, besides just the X being stamped into it.

Anyone know what the X indicates, had to come out of GM like this. Guess I never looked that closely before.