Now that I have the exhaust system done , the headers have a crack

these are expensive , but they are easy bolt on with no clearance problems on a 2970 340 dart , right ? Sick and tired of header leaks and smashed tubes . I can live with 10- 20 less HP if need be ,
http://www.accurateltd.com/340-Exhaust-Manifolds-40Pair41_p_162.html