Its hard to round up all the little stuff. That's what kills you. A bare head is $400 or so. Plus whatever you can find injector hold downs, valves, valve springs, push rods, retainers, keepers, rockers, pedestals, bridges, valve cover w/ bolts, water neck, alternator bracket, valve cover gasket, head gasket (modified for the 24v steam holes), head studs/bolts, exhaust manifold, 24v upper radiator hose, run new heater hoses, and if you use a CR head youve gotta mill the side and buy or build an intake. I'm sure I'm forgetting something but that's most of it.
Plus for high rpm's the 24 valve head obviously has more moving parts so potentially more problems. A ported 12 valve head will be cheaper, easier, and you can make a lot of power with the 12 valve head. If your on any kind of a budget id leave well enough alone.