Found the episode I was referring to if anyone is interested in the story of the Sour straight from the horse's mouth.
It's a long listen, but worth it if your a Sour freak! Long story short tho: "Weasel" meets Chemdog at a Phish show and trades for the 91. Weasel is growing the 91 in NYC but doesn't like the Chem name (organic was all the rage and the name turned people off apparently) so begins calling the orig Chem91 cut "Diesel" instead.
The Albany crew (Manny, Bro, Vondo etc) start buying up all the "Diesel" they can from Weasel and over several batches find and save seeds in a film canister labeled "Our Diesel". At some point (95/96?) they started to grow their seeds upstate, and someone said we can't call this "OUR Diesel" so someone slapped an S in front and that's where it got the sOUR Diesel name.
After that, shit gets super hard to keep track of who got what, if it's the real cut, etc. The Bro and many others say AJs cut is not the same as their keeper from the original seeds, and theirs was the only one they kept or gave cuts out. But trying to figure out which of the cuts circulating today (if any of them) are that original cut isnt easy.
Even more difficult is trying to decipher what pollen may have made the seeds in Weasel's room. The candidates seem to have been narrowed down to DNL or MSSxNL but there is still plenty of debate/speculation