GM A-Body Audio Installation

The GM A-Body cars are at the heart of the Muscle Car Era and remain wildly popular today. But the audio systems of the 60s and 70s left a lot to be desired by today’s standards. We join Mark Simpson and Doug Sjogren in the shop to upgrade the audio system in an iconic GM A-body car. Installing a Custom Autosound USA-740 radio and kick panel speakers in a 1968 Oldsmobile Cutlass Convertible (GM A-Body) is a great way to modernize this classic car’s sound system while preserving the vintage look of the dash. Here’s a breakdown of the benefits and the step-by-step installation process:

Benefits of Installing the Custom Autosound USA-740 + Kick Panel Speakers

1. Classic Appearance, Modern Features
- The USA-740 is designed to look stock but hides Bluetooth, USB, AUX, and digital media support behind a vintage-looking faceplate.
- Maintains the original aesthetic of your Cutlass dash.

2. Bluetooth & Hands-Free Calling
- Stream music or make calls without additional adapters
- Safer and more convenient than period-correct units.

3. Improved Sound Quality
- The USA-740 offers 300 watts of peak power and 4-channel RCA outputs, a big upgrade from original radios.
- Kick panel speakers deliver directional sound toward the listener, improving audio imaging and clarity.

4. No Dash Cutting
- Made to fit the stock radio opening—ideal for preserving the value and originality of your dash.

5. Add-on Expansion Capability
- Easily expand with amplifiers, subwoofers, or rear speakers thanks to RCA pre-outs and subwoofer control.

Installation Process: USA-740 Radio + Kick Panel Speakers

Tools & Supplies You’ll Need:

- Phillips & flathead screwdrivers
- Socket set & ratchet
- Wire stripper/crimper
- Electrical tape or heat shrink tubing
- Solder or butt connectors
- Test light or multimeter
- Optional: dynamat/sound deadener

Step 1: Disconnect the Battery

- Always disconnect the negative battery terminal before beginning electrical work.

Step 2: Remove the Factory Radio (If Present)

- Access the radio by removing the dash trim and ashtray (if applicable).
- Unbolt the factory radio and carefully disconnect wiring.
- Save any brackets or support straps if they can be reused.

Step 3: Install the Custom Autosound USA-740

Mounting:
- Slide the radio into the stock opening.
- Use the provided side brackets and support strap (often attaches to dash frame or firewall).

Wiring:
- Connect power (switched and constant), ground, and speaker wires per the wiring diagram.
- Use the original GM harness (with adapter if needed) or custom-wire it cleanly.
- Connect Bluetooth mic and run to the sun visor or A-pillar.
- Connect USB and AUX cables—route them to glove box or center console.

Testing:
- Reconnect the battery temporarily and test radio operation.
- Confirm power, speaker output, Bluetooth pairing, and controls.

Finalize:
- Tidy up wiring using zip ties or wire loom.
- Reinstall any dash trim and secure radio.

Step 4: Install Kick Panel Speakers

Custom Autosound and other aftermarket companies (like RetroSound or Q-Logic) make pre-molded kick panel speaker pods for A-Body cars.

Remove Factory Kick Panels:
- Unscrew and remove existing kick panels (be gentle with convertible-specific trim).

Test Fit the New Kick Panels:
- Some trimming may be needed for air vent or carpet clearance.
- Ensure door swing doesn’t interfere with the speakers.

Wire the Speakers:
- Run speaker wires from the USA-740 output or amplifier to each kick panel.
- Secure wiring under carpet or along firewall as needed.
- Solder and heat shrink connections for durability.

Secure Kick Panels:
- Screw into place using factory holes or self-tapping screws if needed.
- Ensure they sit flush and don’t interfere with parking brake or wiring.

Step 5: Final Testing

Turn on the radio and test:
- Balance/fader
- Source input (Bluetooth, AUX, USB)
- FM/AM reception
- Speaker clarity and volume
- Adjust tone and volume settings to your liking.

Tips for a Clean Install:

- Add sound deadener behind the kick panels to reduce road noise and enhance audio.
- Use a radio antenna adapter if upgrading the antenna.
- Consider installing a rear speaker system or subwoofer for balanced sound.
- Route all wires away from moving parts (brake pedal, clutch, steering column).