Header ID Help

Those are small block truck headers. I have a set in the shop bent just like them. You can very quickly tell the difference because. the shapes are exactly reversed in the car application, like these.

http://www.summitracing.com/parts/sum-g9040/overview/year/1971/make/dodge/model/dart

Sorry to be the bearer of bad news, but you do indeed 100% have truck headers.