Those are Victor copy heads, and a bit large for an unknown build 400. They do require offset rockers. If you're willing to risk speedmaster aluminum rockers, only around $300.(to the best of my knowledge there are no stainless rockers with the required offset)
If you want good rockers to go with those heads, Hughes are around $1000, T&D around $1500.
For your unstarted, unknown 400, I'd suggest 440 source, or other smaller port aluminum heads.
The current state of the art street 400/440/ stroker head is a 240cc or 270 cc Trick Flow head. Those speedmasters are 50-80 ccs bigger, belong on a 512.
