Sorry Nanket is wrong....the drip rails are where the upper roof skin is welded to the lower structure....when you cut of the drip rail the upper roof skin must be carefully rewelded to the lower structure.

Take care,
Rick
68 Coronet R/T 440 & 68 Charger 528 Hemi,and 5 Challengers! 6 cyl, 318, 360, 383, 451