SpeedMaster Heads for a 5.9 Magnum

Iron head then?
The OEM rockers are fine.
What cam are you considering?

I also run a stock ‘00 - 5.9 long block w/bolt on parts, no cam yet. I outfitted the long block with a small Edelbrock 600, rpm intake, 1-3/4 headers into a 2-1/2 exhaust, junk yard distributor w/a chrome box ignition. 727/3.55’s. It’s very good for what it is.