[Arran]

I gave a Chrysler/MoPar car radio from 1954, it was made by Philco, and it uses two chassis, one has the power supply and power amplifier, combined with the speaker, it uses two 6AQ5s and a 6X4 rectifier, the other chassis is the tuner with a pretty standard 1950s 7 pin miniature tube lineup, plus an RF amplifier, it is slug tuned. The G.M radios I have used octal types, with either push pull 6V6s or 6K6s, the units are self contained with everything on one chassis, I can't remember whether they used an 0Z4 or a 6X5, the Ford ones I have are newer in that they used 12 volt space charge tubes, and a transistor as a power output,
Some MoPar car radios were made by Philco, others by Motorola, no idea about Stydebaker but all are probably made by one manufacturer. Unlike G.M most car makers didn't try to make their own car radios, most sourced something from Philco, Motorola, Bendix, and occasionally Zenith.
Regards
Arran