The ratio. A performance ratio will be 3.42:1 or numerically higher whereas a non-performance is in the less than 3.08:1 range.
A performance rear in 69 was a 3.64 rear gear ratio. 3.64 was the default ratio in 69 stage 1 cars without AC. As far as I know the axles were the same as those in AC A body cars.
The performance axles in the big block 8.2s had larger side gears and a more robust housing for the increased torque/abuse
If you have Limited slip posi... You have the performance rear. Gear ratios are all optional in every rear. Dealer and manufactures had Warranty issues with certain optional items but that was for the customer and the dealer to discuss. Most Auto makers have the Regular and HD performance upgrades... you have the 4 spider gear Super duty posi unit from the standard 2 spider gear regular posi ... Chevy had COPO posi part and gear upgrades... They were special HI PO upgrades for special cars. Ford had there stuff, Dodge same thing...ALL the secret performance parts bin stuff. Jim JD