Hi does anyone know what size the two front dash speakers are? And can I plug some replacements in or do I have to do some wiring? Thanks 1978 Oldsmobile delta 88.

 

3-1/2" though I've heard you can carefully fit 4x6. If the car ever had a factory radio it should already have speaker wires to the existing dash speakers. You'll need a very short Phillips screwdriver and a wide flat blade to pry the speaker cover out.

Popular as the B-body Caprice is, you may be able to find kick panel speaker pods. Caprice and Delta are basically the same car.