The prop that came with the early ’50s 25 horse Evinrude Big Twin/RD Johnson is 277580 – 10-3/8" by 12-½". It is used as a heavy duty prop for cabin boats and barges for the 40 horse model. The six digit numbers that replaced the old Johnson numbers with the dash in them were in the 306 and 307 range. Of course those could be superseded by newer, higher numbers. . . 🙂
