Amazon.com: ECOTRIC Behind Seat Speaker Brackets Square Body Replacement Compatible with 1973-1987 Chevy/GMC C10 Single Cab or Crew Cap Pickup for 6x9 Speakers : Automotive
Behind Seat Speaker Brackets (6" x 9") - Classic Chevy Truck Parts - Tinworks Fabrication
StreetRays.com: [SR] Behind Seat Cab Corner Speaker Brackets Square body FOR 73-87 Chevy C10