Hi Bill,
Nice Trans Am! Love the Concord stereo, too! Great luck with the sale
The Concord HPL-505 had a nice built in bass equalizer, and you could adjust the tape speed on your cassette tapes, too! They were fairly expensive when brand new-and sounded great.
I had one in my 72 Nova...with Jensen Triax II's at first, then infinity separates, later.