What's my point?
You said, "Plenty of LA blocks running 600+ and living a long happy life."
I have now counted three. That's not plenty.
My point is it's super easy to SAY you have a 600hp 360. If you had said there are plenty of claimed 600hp 360s, I would have had to agree.
Way back in the days of smallblock Pro Stock the Mopar guys started having trouble with 2-bolt 340s at around 600hp. They reportedly scrapped T/A or AAR cars for the blocks which had provisions for adding four bolt main caps.
Or maybe that's just a myth.
R.