Timing/Intermediate Gear??

[wideglide38]

Morning all,
I found these two different Timing/Intermediate gears in a 5-gal bucket of cams & gears I picked up. Both gears are 42T with 10T spirals, 2-piece construction, 2.740” Dia. & 1.805” Tall. Bruce’s book points toward p/n 25850-36 (old 621-36). I’m thinking is the left gear is later production and the right early – maybe aftermarket?? Any motor builders run across these different yet similar gears? Appreciate any comments.
Thanks William

[Rubone]

The gear with the continuous spiral is later construction. They totally interchange on any OHV generator engine, Knuckle, Pan, or Shovel.

[wideglide38]

Thanks Robbie, I thought the same. Now onto cleaning some gears & cams!