We purchased a 1978 Silver Anniversary with a little over 13,000 miles on it. All original except the radio and antenna.
How can I find out which radion this vehicle calls for? We do not have a build sheet.
Any help would be greatly appreciated.
B Ransome

 

Without the build sheet I don't think you'll be able to know which exact radio was in your car originally. If the multiplexor/convector/amplifier is still up under the dash, that may help narrow it down a bit. Also, if the original pigtails are still in place that plugged into the radio, that would really help, but they may have been cut off to install the aftermarket radio.
There was a choice of four different radios, all which will fit the same space in your dash.
1- Regular AM/FM radio
2- AM/FM radio stereo
3- AM/FM radio with 8 track tape player
4- AM/FM radio with CB
These come up fairly regular on sites like eBay so finding one shouldn't prove too difficult. If you just purchased the car and it only has 13K miles, did you buy from the original owner or from a dealer? I would think the paper trail might not be too difficult to find out which radio was in the car and perhaps is still sitting on the shelf in the original owner's garage.
Stranger things have happened.
Cheers, Greg

 

You've got the VIN and by contacting the GM Heritage Center, you can get a dealer's invoice for a mere $50.00 and it will list the options ordered when the vehicle was delivered. If it came with a power antenna, brackets would still be in place if the unit was removed. Look under the driver's side rear inside the wheel well, up by the muffler.

This should get you close.

https://www.chevrolet.com/?evar25=gm_com_our_brands

 

Good point. If you find evidence of a power antenna, that would rule out the CB option when the car was new, as the power antenna was not available if the buyer opted for the CB radio. The CB cars were fitted with a special fixed antenna.

 

It's quick, inexpensive, and easy to get your 1978 dealer's invoice from GM Heritage and it will tell you what options your car was built with.

 

I politely disagree. Here is some quick evidence to contrary. These documents come from two different 1978 B2Z Silver Anniversary Corvettes (SA paint doesn't matter but why not keep apples to apples?).







You can see the UP6 RPO code for these CB radio option with Power antenna. I don't recall seeing a non-power CB antenna on a 1978.




Above is the GM Parts Catalog showing the power CB antenna (ELEC -- electric).

Please note that while GM advertised options in pre-production literature like advertisements and brochures some of those options weren't available at the beginning of the model year but were available later in the model year. One example is the Pulse windshield wiper which was including in the Convenience Package. GM wasn't ready with the Pulse wiper until the Pace Cars began build in March 1978. Earlier cars got a credit back from GM for the lack of Pulse in a car ordered with the Convenience Package. I mention this because the 1978 brochure (July 1977 dated) specifically supports C3Hhighway's comment...."Power radio antenna (except with CB units)"...but this was pre-production literature. We could get into researching when exactly GM was ready with the Power CB antenna but the point is that having a power antenna cable in the car doesn't denote that car did or didn't come with a CB radio from the factory.

 

Wow, I stand corrected. This is good stuff, 70s. You come to the table prepared with relevant documentary evidence. Yes, I was thrown off by the 1978 Corvette sales brochure.

So, if I understand correctly, once Chevy had the CB power antenna ready to go, all buyers opting for the radio/CB also got the appropriate power antenna in a package deal. If so, this would explain why the radio/CB option was so much more expensive than even the 8-track radio option. The latter was a fairly popular and expensive type of radio unit in seventies vehicles.

 

The 1978 corvettes did come with a power am/fm/cb antenna... rebuilding two of them now...one year only

 

Actually, thanks to a study of buildsheets, the power antenna came with the CB option automatically and why GM got the $638 for it when the buyer ordered UP6. I surprised when I figured this but the CB power antenna had its own RPO and it was called out when CB was ordered. All other radio options, the power antenna was a separate buy!

 

I jumped on C3 highway before I read all the way down and your post...good work!

 

Plus if it had a 8-track originally the glove box would have stacking in it. Hdal

 

Here's the link to get your dealer invoice. It made a cool gift for my wife's 79.

https://www.gm.com/heritage/archive