The Stovebolt Site Forums The Shop Area The Electrical Bay The Radio Bench 1956 GMC radio Q?

I'm looking for a GMC radio for my 1956 2-ton, and aside from the lame re-pops with chevy glass in them, I cant locate an old AM radio that will fit the GMC dash. Not lookin for fancy here, I'd be happy with just the stock AM radio.

What I did see recently was a decent looking operable radio from a '54 for a reasonable price. Aside from the bezel shape, they look identical. Am I wrong?

Freq2002,
if you are looking to buy a radio, please post your request in the Swap Meet.

I believe that the GMC and Chevy versions of the radio are very similar but I am sure that someone will have more details for you.

1954 GMC radio would have originally been 6 volt positive ground and a 1956 GMC radio would most likely have been 12 volt negative ground.

Sorry, I missed the differences in years. I think that they are different, besides the voltages. However, in tube technology radios, it doesn't matter whether they are positive or negative ground but of course the voltage matters. If there is a solid state replacement vibrator in the set then the polarity matters.

I just wish I could tell it the bezel was different enough to be an issue, or the housing would interfere with the wiper motor. If it will fit I can deal with a Pos/gnd and the 6V vs 12V issue easily enough. Not too difficult to wire it backwards and drop a resistor in there.

A resistor would not be the solution - you will need to change out some internal parts, and truckernix is the expert.

Freq2002,
just to make sure that it is clear, there is no problem using positive or negative ground on these old tube models. However if the vibrator has been replaced with a solid state one then the vibrator has to be the correct polarity. With the 47 to 53 radios, a resistor of around 1 ohm and a rating of about 40 watts does the job. I don't know the actual draw on the 54 radio but it probably would be slightly less .

try this site for a reverence. http://cgi.ebay.com/ebaymotors/47-7...9-71_W0QQitemZ380052745889QQcmdZViewItem ron

1955-59 GMC 12 Volt factory accessory radio includes knobs, bezel, and overhead speaker with mounting screws ect. The dial turns freely and the inside is very clean, the speaker needs to be re-coned or replaced. I don't know if it plays or not but generally the vibrator tube and the OZ4 tube will need to be replaced.

I have 3 additional photos, the speaker, one with the back removed & one of the inside of the back cover showing the tube layout

Contact me at: [email protected]


I took the price out so it didn't turn out to be an ad in the wrong area but at least it gives you a lead on a correct setup.

I am curious as to whether Chev trucks had the same speaker arrangement.

I'm thinking no, might be wrong tho as I tend to look more at the GMCs' than Chevys. I've seen the Chev radios have the speaker bolted to the top face, GMC's have a remote speaker housing (I have NO idea where it should go tho,...). But if I recall correctly the dash on the Chev trucks has a grille above the radio, the GMC dash is smooth and has the ashtray in the middle of it.
Thats some clarification I could use too!

So, a year and a half later,...
My dad found me a guy in KS selling the radio out of a '57 Chev truck for the right price (cheap), and I now have it in my hot little mitts! It's in decent shape, lots of dust but nothing major. The tubes look good once they are clean, and moreover no obvious signs of burnt circutry.

However,... I have the '56 GMC photo fact sheet and sumpin smells fishy here!

Now it appears that the bezels are slightly deeper on GMCs compared to Chev, but the kicker is while the internals are the same critter, the radio is flipped over. GMC radios the beveled front side goes up, in this Chev it goes down. I suppose flippin over the glass and crossing the string is an easy enough solution anyway.

There is a question in this mess.
I'm assuming that the two wires coming out the side are my power wires, white pos, black neg, and the green wire plugged into the bottom (or top?) is the speaker lead. Just wanna make sure before I give it a try.

I found that the remote speaker fits above the rear view mirror. theres a knock out for the speaker magnet and wire and a couple dimples for the lower screw holes, the upper screws go into the headliner. It's not a bad looking instal when it's up there. Running the wire down the A-pillar is a bear though!

I am working on what is supposed to be a 57 GMC radio right now. There are three wires coming out of the main chassis. One is dark or black and it has a fuse connector on the end. This is the main power wire. The chassis serves as the other ground power connectio.

I also have a yellow wire which has a spade connector. This is the wire powers the dial light. The third wire is green and it has a female connector on the end. This is the speaker connector.

OK, sweet! Thanks for that.
I forgot about the dial light. Both the black and white wire have spade connectors on them, was just a matter of fingerin out what was hot and what was not! The speaker wire seemed like the right one seein as it comes out of the output transformer, never hurts to ask!
Gonna go fiddle with it as soon as I can get a fuse holder so I dont nuke it, or let the smoke out as that tech article says.