I want to put some new speakers in my car and was wondering the sizes of speakers for the dash and the rear speakers. Its a 1981 280ZX 2+2

 

I have 5" speakers in the front of my 83 and 7" splits in the back. To fit the splits in the back we had to use a nibbler and cut into the metal. Either way, the whole lots being redone in mine because the car rattles to much. I'm going to have to sound proof everything before I go any further. I'm replacing the 5" speakers under the dash with some custom splits, however i'll have to find some inspiration as to where to put them because the car is a real ***** when it comes to car audio.

 

What is the normal size of the rear speakers without making any modifications?