diarmadhim wrote:
I assume you're talking about the vent slits to the rear of the door openings?
It shouldn't be difficult. a couple ways would be to cut out around them, make a template of it, cut out a piece of sheet metal to match, test fit, tack it in place, check it weld it (keep it cool or it'll warp) a little grinding, maybe a skim of filler, prime done.
or
just grab a tub of Bondo and fill it all in.

There are people here that have done this and can probably give some better instruction...
Maybe by shave, he means strip the paint.When I sanded my truck and primered it, and those vent areas, I coudnt really get in there that well.
As far as Bondo goes, I have a dislking to that stuff, it doesnt last that long, it ususlay crack and the paint goes with it, makeing it look awful.
I saw replace it with steel. Heck you can get metal rocker arm replacements.