There are a bunch of options to junk the stock stereo and install something else. Make sure you order the correct color, unless you plan on repainting. I got lucky and found the pocket and dash piece in a junkyard truck.
A no-brand kit that has a single-DIN dash piece, a pocket to replace the dash controls, an adapter harness, and the GM antenna adapter:
www.amazon.com/Custom-Install-Parts-Compatible-Chevrolet/dp/B0085VALAK/
The Metra pocket to replace the dash controls:
www.amazon.com/gp/product/B00032C2GK/
The Metra double-DIN dash piece:
www.amazon.com/gp/product/B07JFK449L/
The Scosche single-DIN dash piece:
www.amazon.com/Scosche-GM1482GRB-Installation-1988-1994-Chevrolet/dp/B0007KK2AG/
The Metra single-DIN dash piece (in blue):
www.amazon.com/Metra-99-3000B-Dash-Chevy-88-94/dp/B00029X1LE/
The GM antenna adapter by itself:
www.amazon.com/dp/B0002BEQN4
A no-brand kit that has a single-DIN dash piece, a pocket to replace the dash controls, an adapter harness, and the GM antenna adapter:
www.amazon.com/Custom-Install-Parts-Compatible-Chevrolet/dp/B0085VALAK/
The Metra pocket to replace the dash controls:
www.amazon.com/gp/product/B00032C2GK/
The Metra double-DIN dash piece:
www.amazon.com/gp/product/B07JFK449L/
The Scosche single-DIN dash piece:
www.amazon.com/Scosche-GM1482GRB-Installation-1988-1994-Chevrolet/dp/B0007KK2AG/
The Metra single-DIN dash piece (in blue):
www.amazon.com/Metra-99-3000B-Dash-Chevy-88-94/dp/B00029X1LE/
The GM antenna adapter by itself:
www.amazon.com/dp/B0002BEQN4
