A body weight loss

Does anyone have a idea how much weight my 74 duster would lose by putting fiberglass on it? I'd like to go with the least amount of fiberglass so it may be nice to know what glass bumpers are worth, doors are worth, hood is worth, deck lid is worth or front clip is worth. I will probably start from the front and move back. I dont know if anyone has ever done these calculations individually.

I have an Big Block that I want to run an 8.50 class and I think i'll need to get the car somewhere near 2,500 lbs. to do that.


Thanks guys!