Fuselage AM to AM/FM swap

[Daniel Romero]

I have a '73 Plymouth Fury that came out the factory with an AM radio. My goal is to find a factory AM/FM radio, hook that up and just replace the original speakers and use an FM transmitter connected to my phone. I'm wondering if the speaker configuration is different in a car with FM radio compared to an AM radio optioned car? In other words, does the dash have two speakers for stereo? I haven't taken it apart to check yet but I'm questioning if I'll need to make any modifications to the dash or the rear deck to allow for stereo sound. How many speaker connections does the FM allow compared to the AM only?

 

[Davea Lux]

I have a '73 Plymouth Fury that came out the factory with an AM radio. My goal is to find a factory AM/FM radio, hook that up and just replace the original speakers and use an FM transmitter connected to my phone. I'm wondering if the speaker configuration is different in a car with FM radio compared to an AM radio optioned car? In other words, does the dash have two speakers for stereo? I haven't taken it apart to check yet but I'm questioning if I'll need to make any modifications to the dash or the rear deck to allow for stereo sound. How many speaker connections does the FM allow compared to the AM only?

The R11 option standard radio package has a single speaker in the dash, with an additional rear speaker as another option. These are Monotone speakers only. Also the wiring harness to the speaker(s) will have a different plug configuration and probably a different number of wires. Most FM stereo systems of that era used four speakers to get the stereo effect. Two were mounted in the rear deck and two in the dash.

Dave

 

[CBODY67]

I'm not specifically sure about the '73 Furys, but prior C-body radios went this way.
Base radio was a single front speaker AM. Rear speaker optional.
Next option was a mono AM/FM unit, rear speaker optional.
Then came the AM/FM Stereo. 1 lh speaker 1 center speaker 1 rh speaker (front) On some, this was the basic "stereo" set-up, whereas on others, it added a fader and 1 lh and 1 rh rr speaker. I believe on the C-body cars, the basic stereo was the 5-speaker set-up.

From that, the tape unit radios came into the mix. The '72s had the center-floor mounted stereo record/playback cassette. 8-track was gone by then.

My '70 Monaco had the basic AM radio and factory rr speaker, so the infrastructure was already there for the factory AM/FM Stereo (bought new when I still could in '76) I added. It's NOT as easy as the '74+ vintage stereos, which had 4-speakers and integral f/r fader!!

The back of the radio had one plug for the speakers. L-R-Ground. From that connector, a harness went to the "divider box "(Clecktron) that had wiring that went to each of the front 3 speakers. From there, the wiring went to the stereo f/r fader control. Then I had to build the harness going to the back speakers (no a big deal as that was the only piece of the system that was not available). I also ordered new Chrysler speakers. 3.5" for the outboard front and 6x9 for the rear speakers.

Not having the 3-speaker instrument panel pad, I hung the front speakers off of the metal housing of the instrument panel, at each corner. The center speaker was the existing speaker. Having the front speakers "in-baffled", hanging in "free air space", their sound was a little weak compared to the rear speakers, so it was tricky to balance them against the back speakers. But when it was done, it sounded great with the stereo spread across the windshield area. The frequency response of the Chrysler factory speakers was much better than either Ford or GM, especially GM.

For the '74+ model years, the new stereos were conventional 4-speaker units. 2 frt, 2 rr, with integral r/f and r/l fader/balance controls. MUCH easier to wire and use. I did that upgrade on my '80 Newport.

So, not as "easy" as might be suspected. You can find the factory wiring diagrams online if you don't have a factory service manual.

ONE thing about the Chrysler wiring for the radio and speakers. The insulation is very thick and robust with larger wire itself. Very nice stuff AND better than many aftermarket units, by a long shot. I matched the gauge of the wiring and used OEM-spec connectors in what I did. No problems at all.

CBODY67

 

[Sixpactogo]

I have an AM/FM radio from a 73 Plymouth wagon. PM me if interested. $80.00 plus shipping. I don't believe these were stereo so only used one speaker in the dash and one in the rear. Don't quote me on it though.
Here are a couple pics.
Tested and plays on both bands

 

[bigmoparjeff]

AM/FM Stereo radios were quite rare in Plymouths and Dodges before 1974, so it's going to be hard to find one. Going with a mono radio may be the best bet. The mono radios were generally better at holding a station.

 

[CBODY67]

One thing, back then, was that it might highly depend upon where the car was sold. My Monaco was sold in far southwest TX, so it got the normal AM w/rear speaker (basic group) item (FEW FM stations). Several hours north in either Midland/Odessa, Abilene, or Lubbock, those areas had several popular FM stereo stations. If it had been ordered/sold in Dallas, it would have had the AM/FM Stereo. Otherwise, it's got the Brougham Package, power lh seat, power windows, power door locks, but no optional clock. So, the only option really missing is the stereo radio. By the later 1960s, almost every metro area had a large selection of FM Stereo stations. Many were "rock" music, rather than otherwise. Many were also moving up in broadcast power to 100K watts, for best reception and about 70 miles of range (which the Chrysler radios seemed to be very good at).

If the car was a "customer order", what it got would have depended upon the desires/needs of the future owner and their listening habits.

Those are my observations from "down here".

CBODY67

 

[ceebuddy]

Just a side note:

Even the stereo radios designed for the "Multiplex" setup (those that use five speakers total - three up front and two rear speakers) only have two wires for the audio signals (left channel and right channel), plus one common ground wire. They do not have four channels coming out of the radio (for four speakers) like more modern radios have.

Instead, these units used an external "crossover unit" connected to both the radio and the fader switch. It's a metal box about 3"x2" in size. It served to merge the two channels (left/right) into one signal for the front center speaker as well as to allow for front/rear fading while at the same time allowing left/right balance (which is controlled by one adjusting ring of the radio knobs).