I know a former NHRA E body stock class record holder that removed over 40 lbs. from his 1971 Challenger doors and still got through NHRA tech and NHRA tear down inspections when he would set the class records, them dang E body crash door bars are heavy
He strip that car down to a bare shell and only put back in what he thought the car needed to get through NHRA tech.
That car was really lightweight for a E body, he had to add over 180 lbs. ballast to be legal with him in it and he was not a lightweight driver