MP was the last seller that I am aware of, for USA origin B/RB water pump housings.
The last place they were made was the same California facility that also cast and machined the M1 intake manifold line.

All gone now.

The older Direct Connection housings are cast pretty roughly and are a little bit thin compared to the MP pieces. I don't know where
they were cast as that was before my time, but it had to have been from different tools than the last MP housings.