It's the 6.4 head. Has larger valves, and a very nice runner, port etc. The valve guide is moved up into the spring leaving a very smooth port. That part might be available as a 'recon' only, which means it will be new w/valves, but you need a like number core. Mopar is trying to get some made for racing as bare. They were originally ok for stock till someone looked at them. Send me an email and I can give you more details if you want them.
jefft@southlanddodge.com Supply has been a problem for all the Gen III heads in addition to others.