My 422 smallblock build
Bummer man seriously. Don't give up hope though. You still have most of the expensive bits there. Rocker gear, valves, springs, etc. Source a head, get a new head gasket, use a hoist to yank the old head out. It'll be back together before you know it.
There are a couple of W2 heads W2 engine groups on Facebook, you can probably find a replacement there. Post in the wanted ads here, and possibly the racers forum. You'll find a replacement.