All blocks for 1961 and 1962 including SD's had a 538181 casting number.
All non-SD heads for 1961 and 1962 had a 538177 casting number.
Are you sure there's no numbers at all on the front of the block? For those years there should be both an engine code and the VIN, they could be covered up by paint, rust or grease/dirt. I've never seen one without them, could it possibly be a service replacement block?
|