Which stroker kit for 470" b-engine

The volume of the runners is what needs to be looked at, a smaller cubic inch motor doesnt need huge ports to make power, unless you are really going to wind it up, a bigger cubic inch motor can use the larger ports and keep the power in a lower rpm range, all depends on what you want to rev it too, having them ported will help, no doubt, but for 550-600 i think you would be fine with what you have,