K10 Dash Speakers

Hey Guys, I'm trying to install a new stereo in my 84 Chevy K10, but I need to know what size speakers are in the corners on the dash.? any ideas? Also, do I have to have a special mounting bracket to install the center dash speaker?

http://www.crutchfield.com they will tell you what speakers, prob 4x6, dont order from crutch field there expensive. I replaced my 88 with pioneer 4x6's and loved them

Thanks, I found its a 3 1/2 inch. I tried looking all over the net earlier to find that size, but couldn't.

You may need to modify the cut outs