Careful about surfacing heads. Only do it if necessary (warped). There is no combustion chamber like gassers have, but you need to keep track of the valve projection. The valves stick out from the gasket surface. If you do not do a valve job at the same time, they may hit the pistons. It has happened.
Also check for cracks in the heads. The 6.9 heads were prone to cracks between intake and exhaust seats. Have the machine shop magnaflux the heads before going too far into the project.