Hardened Intermediate Shaft for 318/340
Fyi that is not a hardened intermediate shaft in the picture. A hardened shaft is ground at an angle into the hexagon at the bottom. This one stops and then has the hexagon tip. Also I do not see a pin through the bottom of the gear pinning the shaft to the gear. A generic photo in other words.
Mancini sells the hardened shafts.
Mopar part # p3690715
Mopar Oil Pump Driveshaft & Distributor Gear