yes you can the size is 6.5". all you gotta do is remove the screws in the handle and arm rest then gently pull off the panel.
4X10's
All the speakers in a 1991 Chevy Silverado should be 4x6 if they are stock.
6X9's
Generally, a stock silverado will have four speakers; two in the dashboard and two behind the seat.
The size of the stock rear speakers in a 1991 Chevy are 6"x9". You can go to crutchfield.com for any other car stereo needs, just provide the site with some information on your car's year, make, and model, and body. From there they will provide you with the correct speakers that will fit your car. I hope that has helped!
Actually...The front speakers are 5 1/4" 4 Ohm speakers and the tweeters are .6" 4 ohm tweeters. Door speakers are easy to replace, but the tweeters are impossible to find the size. Rears are 10 ohm 6 x 9" Ovals. Good luck finding 10ohm though...Can't be found. I have not yet changed the back speakers, but the front speakers are 6 inch speakers. The stock speakers are 4 ohm. Im not sure about the tweeters and rear speakers. Just pull them out and look at the back.
Answer If I'm not mistaking the dash board speakers on your car are under the dash, close to the windshield. I think you would have to remove the entire dash to be able to get at them so do yourself a favor, put good speakers in when you install them, as taking the dash apart is one heck of a job.
Tie wraps can be used to replace a stock radio wiring harness in a 1991 Mercury Tracer. The wires can be replaced with other radio wire from an automotive parts store and the tie wrap can hold them together.
An educated guess: 5 1/2 inch round - this is the case in my 1992 Corolla.
install a well built C-6
a 1991 buick skylark has 4" speakers in the dash and 6x9's in back
The speakers in the doors of a 1991 Ford Ranger are 6-inch speakers.