The long one is the correct part. That's what came with the NAPA kit.
In researching parts sources for the build I found two different style clutch kits in the market:
neither resembles the parts depicted in my '29 to '49 Parts Master catalog.
When I tore the engine down in '12 I found an aftermarket clutch. Photos of the linkage before disassembly showed the adjustment nuts nearly halfway down the threads on the offset rod.
I visually compared the NAPA parts to what came out of the car - nothing 'looked' outwardly different. Very curious . . .