stock radio questions for 73-87

[Laser145]

Howdy

I'm looking for a stock AM/FM radio for my 76 K10. Were the AC Delco radios the same through those years? Any changes I should be aware of?

Also interested in having new internals installed so I can run my iPod to it, power better speakers, etc... I've seen links advertising these services but many links are old.

Anyone recommend a place?

Cheers

[motornut]

the early radios used the chassis ground for the speaker,won't be correct but get the later ones,with plugs for power/fronts/rear.
watch the speaker ohms rating too 8-10 stock

[Laser145]

Thanks for the heads up.

They're all the same size? so my dash opening in my 76 will be the same as the models through the 80's? I read somewhere that the units without cassettes weren't as deep and therefore easier to fit behind the dash of a truck with factory A/C.

[ray_mcavoy]

Yes, the stock dash opening stayed the same in these trucks from 1973 up to 1987 ... and up to 1988 in the R/V series. A lot of GM cars from the early 70's into the mid 80's used the same size radios as well.

The knob/shaft spacing is 5-3/4" on center and the rectangular center opening is about 4-1/2" wide by about 2" tall. The face-plate fits up behind the dash opening (instead of sticking out through) so it's normal for it to be a bit larger than the opening.

The radios with built-in tape players (8-track or cassette) do have a physically larger case. So yes, they can be more difficult to remove/install in a truck with AC.

John (motornut) is correct ... the factory radios use 8 to 10Ω speakers and the early ones (up to about 1977) use a chassis ground speaker system. The 78+ radios use a "floating ground" speaker system and will be damaged if any of the speaker wires are grounded to the chassis.

Most of the stock 73-77 radio connectors look like this:

A 3rd plug (not pictured) was used with some of these radios that had provisions for rear speakers.

While 78-up look like this:

The top (blue) connector is for rear speakers (not used on all applications)
The middle (white) connector is for front speakers (some trucks only use 2 wires on this plug if they have a single dash speaker).
The next to bottom (black) connector is for power/light/ground. The color codes are yellow=switched +12V, gray = dial light, and black = ground. This is the same color code as 73-77 ... just a different style of plug.
And the smaller black connector at the bottom is only used on radios with a digital tuner. The orange wire is constant +12V for the clock/station memory. The brown wire is a "lights on" signal to dim the display.

[Laser145]

Thanks for all the detail!

My plan is to buy an original radio and have it's internals replaced and modernized. Just trying to get my options straight.

Cheers

[RetroMfgWil]

I know you have your mind set on getting the internals modernized, but if you're not familiar with some of the radios with newer features out there. Take a look at them as an option.
We manufacture new radios with the classic look to retain the OEM styling that is specific to each car.
Our top of the line radio has bluetooth, ipod control, Aux and USB connections. We are also introducing a model that will have SiriusXM satellite ability later this year.

[SilverMiner]

Originally Posted by RetroMfgWil

I know you have your mind set on getting the internals modernized, but if you're not familiar with some of the radios with newer features out there. Take a look at them as an option.
We manufacture new radios with the classic look to retain the OEM styling that is specific to each car.
Our top of the line radio has bluetooth, ipod control, Aux and USB connections. We are also introducing a model that will have SiriusXM satellite ability later this year.

I'm the happy owner of a Retrosound Model One (older model, apparently replaced by the Model Two) for the past 2 years, so I would recommend checking them out as an alternative to going through the hassle of gutting an original GM unit. But if you do decide to go that route, please keep us all informed here. I don't even know how that might be accomplished, so I'd be an eager reader although I have no need to do it myself.