Well I thought I had covered all the bases, but we will elaborate.
All under the running board antennas were the same design. Lengths and other considerations were dictated by the year of the car.
Could you visualize a truck with an antenna underneath headed out across the watermelon patch. Probably have it drug off by the time he hit the cantaloupe row. 1st truck radio was 1937.
Two post cowl mount antennas were different lengths as demanded by the model radio installed. The side post you saw with a chrome base was either a Philco or Motorola.
The 1941 side post antenna used an uneven post with an eye bolt. Unlike earlier models the cowl of the 1941 had more curve to it and required a longer stand for the top post to make the antenna vertical.
Where all the side mount whips from 1941 to the last one the same?
No, see answer above.
The single cowl mount antenna was the choice after 1941.
The "over the top antennas" were not very popular as they were prone to being ripped off by low hanging branches and other obstacles. Check the Owners Manual for the radio for specifications.
The reel antenna was only available for the 1941 car. All radios for 1941 included the antenna and installation in the price.
When you purchase a radio, are you already have one in your car, it would be very beneficial to purchase an owners manual. If you have access to the G&Ds from about 1980-85 you will find an article about each model Chevrolet radio written by the chevradioman.
