Kodak's Data Sheet for Panatomic X recommends D76 1:1 for 7 minutes at 68F in a small tank. Best bet is to do a clip test just to make sure that the time is correct due to the age of the film. Being a slow film there should not be to much loss of speed in the ASA/ISO.
Gord
After checking with my 1974 Kodak darkroom dataguide, you have your choice
Microdol-x 1:3 12 mins @ 68deg. F
Microdol x or D-76 1:1 7 mins @ 68deg. F
HC-110 dil B 4m 15s @ 68deg F
Of course, there are adjustments to be made for enlarger type, lens flare, paper type,etc you know-- all the usual factors that Kodak wants us to think about .
Hope this helps.
Rick
Nobody here mentions it but there were a lot of people who loved PanX in Rodinal back in the day. I have a lot of frozen Pan-x 120 that is going to ebay someday.