318 Poly A engine in a 67 Cuda
Just for reference, the cores for the Poly and the LA are the same. That’s why the lifter bank angles are so jacked up on the LA. It’s a Poly core.
The only thing lighter on the LA blocks is the cylinders. They are generally thinner.
Whatever power a poly will take an LA will take.
Not many production blocks will take 700 hp unless you believe in Santa Claus.