Fox Upgrading the Fox Body factory Head Unit and Speakers


Dec 30, 2020
London, Ontario
It's time to replace my 1987 Mustang's factory head unit and speakers. Can hardly see the head units display. To my surprise, I opened up my door panel speaker cover to find out - no speaker. Ha. I wanted to check the door panel speaker magnet to measure its depth so that I may replace this speaker with a speaker size that would not interfere with the function of the window up/down. So my car has the dash 3.5" speakers and the rear 6X8" speakers only. I want to replace the head unit and add an amp and I was planning on replacing dash/door and rear speakers. I'm sure I would be happy with decent speakers with about a 50 watt RMS rating. My Fox is a hatchback. For you guys/gals that have updated your approximately 30 plus year old factory stereo, what did you do? Did you add door speakers in addition to replacing the rear and dash speakers. Just replace and upgrade the current rears and dash speakers and call it done? Or did you just add door 6.5" and replace rears and call it done? It seems the dash 3.5" speakers aren't very common anymore. I didn't remove my door panel, for the Fox Mustangs that did not get the factory door speakers, would you know if the factory speaker wire is still run into the doors that could be used when installing door speakers or do you have to run your own speaker wires into the door panels? Thanks.
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CarMichael Angelo

my rearend will smell so minty fresh,
15 Year Member
Nov 29, 1999
Birmingham, al
if you actually care about fidelity, the factory wiring is crap. The old assed factory wires in the car have oxidized to the point of no longer being able to adequately move the current to the speakers. Most aftermarket installs will replace the factory 20ga. wire with 18 ga. The 3.5 speakers have never been worth a crap IMO, and are at best marginal even when replacing them w/ aftermarket units. I have 6.5” component speakers in front, and tweeters replace the 3.5” factory units. Factory 6.8’s are odd balls too, and the best pieces to replace them with that actually fit are just warmed over stockers. 6x9’s are the typical premium aftermarket replacements, but probably won’t fit, or will require some creativity to make them fit.


Put lubricant all over the balls
Mod Dude
Feb 18, 2001
The stock head unit has a bulb for the display. Yours is likely burned out. Mustangs with the premium stereo setup got 6 speakers and an amp behind the original radio. The base model radio lacks the amp and door speakers. Sounds like that’s what you have.

I would start from scratch. Do not reuse any of the old wiring it’s not worth it.

Also, list your stock stuff on eBay. You’ll be surprised what you get for it.
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Active Member
Sep 13, 2020
Thompson's Station, TN
I did a Kenwood Bluetooth only head unit, soundtream 4 ch amp (75w/ch), infinity 6.5 in doors and silk dome tweeters up-front, 6.5 infinity in the rear. Door/tweeters are components and have a crossovers, rear ive adjusted at the amp. Plenty of volume, have a powered 10" Fosgate sealed sub in the trunk (mine is a vert). Pretty happy with quality and volume. Good luck.