From what you describe with the crank out windshield, heavy duty bumper with grille cut-out and the olive drab paint, My guess is that it looks like
THIS ONE and was used in the military.
HERE'S ANOTHER ONE If it isn't the military style, it could be
THIS MODEL You might want to start hanging out in the
BIG BOLT section. They wll be a great resource for you in the future!
Go to the
GALLERY and check out the different years, better yet, post some pictures.
