Question on drivers side exhaust manifold gasket

Early or late 340 manifolds? They're different.
So first off, see if it clears the manifold.
Then lay it on a 340 head, you'll see what has to be removed. If I remember correctly, early 340 heads (X, J) have ports that will outsize those gaskets. Later 340/360 heads you may be safe with, and may not even require modifying.