Yo!
You could build these,...
http://67-72chevytrucks.com/vboard/s...=301610&page=7
starts at post #162.
They were EASY, sound great, and look pretty good (even if I do say so, myself!).
It's nice having that much speaker in each corner and I didn't have to cut up my doors or the panels (mine are original factory, and irreplaceable green!).
Happy New Year!
Todd.