I drive an 85 single cab with 2 12's behind the seat, its not quite all the way back but the subs don't slap the seat. just get a box made for a single cab. I got mine from hifisoundconnection.com
http://www.hifisoundconnection.com/S...id/0/SFV/30046
Thats the same one I have but mine is for 12's not 10's