A typical number of a 55 235 would be 3856233 or 3836340 for a 261. The 230-250 have something like 3854036
What you got is not the casting number or it is no chevy engine.
The casting number should be close to the starter.
Have a look at the pushrod cover.
If it reaches up to the plugs It´s a 216
If it is lower and reaches only under the head is a 235
If it is splitted (2) it is a post 62 engine.
If you got a 235 or 261 you need a short water pump (give Tom Langdon at Stovebot Co a call he also got a fix for your pulley groove problem)
Frank
