Exhaust manifolds

I bought a 71 318 for my 72 Demon.
It has j heads and, from my quick research, 340 / 360 exhaust manifolds. At least one of the manifolds I have looked up says it's for b / e body..
Is this going to be an issue going in my a body..?
Here are the manifolds and their numbers..1118211931~2.jpg 1118211929~2.jpg