Well shit - the 5.3 I have for this this probably garbage. Pulled it out of the stang this afternoon to start cleaning it up, and swap the cam/valve springs.
First problem - the engine wouldn’t turn over. I pulled the valve train and the rings were stuck for sure. 20min soak with pb and she broke free and spun okay. I wasn’t happy about it but decided move forward as planned and swap the cam. The cam had a lot more resistance than expected, I had to give it a pretty good tug to break it free. There was some noise, but I thought it was hung up on a lifter, nope - this pos spun the #3 cam bearing and it cam out with the camshaft.