Who knows their oils/greases

I would like to know when the rear end greases discontinued using sperm oil. Ya know the type you could put it in and forget it. I just picked up a couple of bottles of Ford limited slip grease dated 1966.
Thanks

 

I heard 1972.

 

The original Ford additive was blue, in a one ounce ? plastic bottle. It used to be spendy, if I remember correctly?..Whale Oil for traction-locks.......OLDBEET

 

Texaco has two products that are suitable for this.
Multigear EP SAE 80W90
If you want a synthetic, use Syn-STAR GL 75W90
Both meet requirements of limited-slip differentials.

 

Probably got discontinued after people became concerned about Sperm Whales becoming extinct.
I'm sure modern science has come up with something better over the last 30 years.