68-70 Hi-po small block 340 exhaust manifolds 2863553 2863549

Don't know....It honestly looks like it was cast that way from the factory....But it does look like a crack from the outside.....need a tiny mirror with angle tip to look inside and see what it looks like on the inside...Honestly if I was going to use this manifold I would grind this down flush and see what it looked like and weld it if necessary....The area is actually raised a little ....like it blew outward....don't know the history of it so I can't comment on it