Vehicles with the Heavy Duty towing package came with the police style external transmission cooler and generally came an A727 and decent gears in the rear differential (3.21 or 3.55’s). The gear ratio is not a for-sure thing, though.
My wagon has 3.21’s and it is fun to drive in-town in.
The external transmission cooler will have two metal 5/16” cooler lines go up alongside driver’s side of radiator, across the top of core support (see white circle on picture, below) and down to a cooler that is attached underneath the bracket that hood latch is attached to.
The rear speaker(s) can be either a factory installed or a dealership installed option. Same parts used either way.
You have me eager to look at your fender tag, now.
Not in this post (so go start another post in the F-body section) with either a good picture of your fender tag (which is not far from the cruise control servo) or write down all of the data on it, in order it shows on the tag(s).
Here is where the fender tag is located at on my wagon (red arrow).
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BudW