they are all boxe frame .my 85 king cab is boxe frame
my 87 dually (1 tone ) is a box frame
and my 84 dually (1 tone) is a box to .
any v6 since 87 to 97 are boxed frame .
and for the 720 model any king cab are box frame 4x4 i don'T no because i don't onw 1 .
2WD FOR EVER !!!!!!