LOL! I miss-read your post. I thought you were asking which Torque Converter to use, that is why I was talking about stall speeds. Ops my bad!
My 5.9 came from a rolled over 2000 Dakota R/T. I got it complete wires and computer and all for $1,000 about 7 years ago or so. I rebuilt it just in case and good thing the machine shop found cracks in the heads at the valves seats. So under warranty still I got New/Rebuilt heads free from the junkyard. They were mad I had it all apart within the 7 days of warranty. LOL