I had a gutted 72 Scamp 340 that was set up as a drag car and it was 3000lbs with enough fluids in it to drive it , the only thing it really had other than working lights was windshield wipers. No heater, carpet, 904 trans, plastic fuel cell, drum brakes ect. If I had turned that car into something set up for road racing my guess is it would pick up a least 100 lbs in brakes and tires, 20-30 lbs for sway bars and increased in torsion bar size, 20 lbs for a better cooling system and accusump, plus the extra weight of a 4,5 or 6 speed transmission over the 904 say 30 lbs. That would put it in the 3150-3200 lb range, I could see a completely gutted E body with small block with lots of fiberglass weight something in this range if you put your mind to it.
Now my guess would be just like my Scamp after you would go through all this you would end up leaving in the corner of the garage as no one would want to drive in it for more than 10 minutes.