I think one glaring omission on GMs part with the ZL1 is the fact that it doesnt come forged from the factory. I mean wtf? For the money you would expect it to be stronger. You cant do much past a tune, pulley and the normal boltons without blowing it up. Blower upgrade on the stock motor? Forget it.
The top end mustang has been forged from the factory since the 03 cobra and even now the boss 302 comes forged from the factory for 20k less than a ZL1.......
That, in my opinion, was one of the biggest mistakes GM made with the ZL1.
Not sure about the info on the LSA strength. We have multiple Vs running over 600 rwhp and up to 810rwhp on a twin turbo LSA with the stock bottom end.
You do need to upgrade the injectors as the OEs are close to maxed but that is an easy fix. Some owners try to pulley/tune with them and that can be a problem.