Are girdles generally added for big rpm or HP or torque

Andy F likes the cross bolted main caps. Better than a girdle.
Requires some drilling on the side of the block. What horsepower level are you shooting for?
He's probably using the ones from Program. They're the best solution I've seen for big blocks. I was thinking the y block idea for LA/Magnum blocks. There's never going to be a bolt on solution that doesn't require at least line honing.