Denny,
the radio on the old chevy manual site is listed as "1951 GM auto radio" but the link isn't working. I will send you the information by Email.
The radio is different from the standard AD radio that we usually think of. The radio has a lot in common with most of the other GM radios of the time. If you look at the chassis of the AD radio for 1951 to 1953 you will see an extra punchout that is empty. That is probably for the second output tube.
Fred
