Rad support # (it's a partial VIN) should be pretty obvious, unless there's a ton of paint or the upper yoke was replaced
From my research LA built ('69) B-bodies had the "A9XXXXXX" last characters of the VIN stamped ON TOP of the radiator support on the drivers side NOT on the backside of the support. My LA built '69 GTX has it on top and I didn't know it, I had asked my friend to check for it as the car was in Texas and I had told him where it should be on the backside he came back and said he couldn't find it
. I got nervous and disappointed but when I got to the car I found it on the top of the radiator support driver's side. Then I started to notice why the engine coolant label was off to the center of the top of the radiator support on LA cars and always more to the far driver's side of the support on St. Louis, Hamtramck and Lynch Road B-bodies.........so the LA B-body had the VIN where the other plants put the engine coolant info label if your looking for it.
This is where the coolant info label is, more toward the center of the rad support, on LA built cars and the VIN is toward the top side of the driver's side, (where the other plants put the coolant info label).
Mike
