235 stamped number

Talking to a guy on the phone about a 235 he has for sale. He said the number stamped on the machined surface behind the distributor is J2306. He can't read the cast in number.

Can anyone decipher this please?

 

My Hollander says "J" is a truck 235 anywhere from 1957 thru 1962. I assume he can't read the casting number because it has the 3 bolt side motor mounts on it and the casting number is behind the passenger side mount? which would make it a 58-62 block. The date code is above the starter...