I blew the same gasket about 6 months ago, then a few months later a head gasket.
Its a rebuilt 351w with a single plane hirise manifold running straight gas. I rarely flog it. I actually heard it blow this time, when i was doing 115kmh on the Hume. its a distinctive loud tapping noise that occurs under load, and is silent at all other times. Annoying as hell.
I fitted felpro gaskets between the heads/block, inlet, and exhaust when repairing the blown head gasket. Made in USA...
Advice?