I think a W5 type head would be a great spot to start from. A standard intake will fit a w5 if it is redrilled to a factory pattern, so on the intake face on a new casting put the bolt holes in the factory location. The header problem could be solved on the new casting by using a magnum style port outlet. If it had to have chevy style rockers I could live with it if provisions were left in the head to use a block type shaft rocker system like w2/5 heads, or even better, big mopar on small block shafts like the victor.
An affordable small mopar head that starts at about 300 cfm and is easily ported out to 350 would do very well. the current buy in price on a 350 cfm small mopar head is about 4500 bucks.