ATK 5.9 Magnum crate motor horse power

TT5.9mag said
The EQ heads are not being produced anymore last time I looked.

They still show on EQ's webpage, which shows "Updated 1/1/2020"

Stock | EQ Cores & Recycling

Also, the JEGS heads are almost certainly made by EQ. They specifically mention that these heads address the OE cracking issue.
https://www.jegs.com/i/JEGS/555/514222/10002/-1