Why is one 340 connecting rod bronze color?

Tony's spot on... My first Mopar involvement,was a PAW parts supplied 340... Ate a pushrod,on one of those damn intake manifold cooling trays... Knew the guy,that built the engine(on a budget). Upon teardown,6 of the 8 rods were copper dipped. The owner of the car was younger than I, said they had been doing it for years...(His old man ,ran a Max Wedge powered 61-2 Lancer for years at Famaso..The man was a crazy driver.(still remember the bumps on my forehead,from doing 100plus in the Pismo dunes in a Chevy powered rail,lol...)