400 stroker

Looks like it stays flexible, like Hylomar. That's good. The problem with the steel gasket between cast iron and aluminum, is the different expansion rates between the 2 metals. This stresses the gasket, and eventually leads to a coolant leak, or worse. The MLS gasket has several layers, and allows the 2 metals to slide past each other smoothly, with the expansion/contraction from temperature changes.
I've always used silver paint with the steel shim gasket. But it was always with cast heads. And have never had a problem..