How much is a 71 lemans 4 door worth with a 400 .030 over

Unfortunately the four door drops the value right in the basement,most of them were used for parts, but if it's in excellent condition, body, interior and drive line my guess would be around $2500 to $4000

Base Le Mans 4-door sedan: not so much. If it's a Luxury Le Mans 4-door hardtop with lots of goodies (A/C, power windows and seat, etc..) along with the original fender skirts and wheel covers, perhaps a little more than what CamaroCollector quoted. The key is finding someone with money that has fond memories of a '71 Le Mans 4-door.

4 door pillarless hardtops would have far more potential than sedans.