Thanks, George. I checked them out, but all they do is confirm that this is a B20B block. It's age is a moot point now , however, because some more exploring revealed that this thing has been rebuilt -- red silicon sealant instead of regular gaskets. I hate the idea of having to open up the front end and pull the camshaft to settle the matter of its identity. I suppose I could pull the plug at the other end and take a peek at the marking. Do you think I could make a determination by measuring the lift on the push rods? The head is off and disassembled, ready to go to the machine shop for valve work.
Bob S.