In the dash, they're 3.5" round, doors I believe are 5" round, and the back speakers are 5x7. Unless you've got the premium sound option, you probably don't actually have speakers in your door.
www.crutchfield.com has a section where you can put in your car type and year and it will tell you what size speakers originally came in the car. Very handy! It doesn't go back to 1966 models though. LOL.
__________________
66 Coupe - CandyApple Red, 2 barrel 289, C4.
66 Coupe - (father-daughter project). Tangier Orange, 302 with AOD, 17 inch Bullit wheels.
69 F-100 - 351c. Emerald Green Metallic paint. Still "in progress".
68 Barracuda - Rusted out project. 318 in the frame rails for now. Maybe a 360 in the future.
00 Mustang - (son's car) V6, 18 inch Saleen wheels.
does anybody know where is the factory subwoofer location on a 2002 ford mustang that has the original mach 460 sound system i found the amps in the back but people keep telling me that my car has a subwoofer somewhere because of the awesome bass sound my email is juan070771@yahoo.com. thank you car nuts.....
is it possible to install the factory mach 1000 sound system in a 2002 ford mustang that has the factory mach 460 already in it. i would like it a little more loud.
Mustang Stock Speaker Sizes 
