Picked up a reproduction RAJO Model 30 rocker arm at the famous swap meet in Chocolate town. Was this rocker also used on the Model 31?
Both utilize a single bolt for the rocker arm shaft support verses two bolts on the newer Model B.
Bill, Are your rockers 1:1 or 1.5:1 ratio. I have a Model 30 Rajo head with 1:1 rockers, but have pictures from about 12 years ago of rockers of the same style that are 1.5:1. I think the Model 31 may take the later style 1.5:1 but don't know for sure.
The 'reproduction' rocker is definitely a 1.5 to 1 ratio like your second photo.
I am 'guessing' the Model 31s used this as well.