6.5 in Front 6x8 in the rear.. Just swapped mine out in my 93 a lil over a month ago. 4x7's Will fit in the rear also(some boxes will tell you they will fit 5x7 And 6x8 speaker holes).

 

the bigger, the better they can handle the lower notes, or in this case, mid range

 

ya what he said... bigger the better with proper amplification behind those speakers. Don't forget to add sound deadening to your floors and doors.

 

Attached is a rough sketch with what you have to work with in the factory trim panel.
Mounting screws are essentially spaced vertically 4 & 3/16" apart and horizontally 5" apart.

The oval opening in the Panel is 7 & 7/8" tall and 5 & 1/4" wide

Looking at a number of different sites; It appears most 5" X 7" and 6" X 8"
speakers would fit.

Best of luck.

Todd Stranczek

 

Old post I know, but for those doing the back speakers and the tweeter sticks out or they dont seem to fit right, I removed the plastic spacer that is glued onto the factory speakers, put spacer on the new speakers, lined them up and tightened them down to the panel(Infinity reference series) and fit like stock.
I used a knife and slowly worked my way around speaker till the plastic spacer came off, is pretty easy and the glue isnt the strongest,but I didnt want to crack the spacer so did it slow

 

Im going to have to do this. My rears nudge into the exterior metal. When I did it I pulled the mesh out. Looking back, there's got to be a better way. Do you have to remove the seatbelt bolts to remove that plastic or what?

 

I put 6x9s in a 93.

 

Are there speakers in the rear of an 87 ext cab? I only know of speakers in the door of my truck and i think they are 6.5s. Kinda sucks if that's all there is...

 

I didnt have to remove seatbelt bolts...4 screws on speaker cover..unplug..remove and install the new ones. The stock speaker has the spacer glued on it..is the black plastic ring around top of speaker..about 1/2 inch.