You will need an adapter to go from the spread bore manifold to the square bore carburetor or find an early 340 intake. The intake you have has larger ports than your 318 heads. It will work, but won't be ideal. If you are going to stick with the 318, at the very least you should add 360 heads when you rebuild it to match the ports. I do have a '69 340 intake that I am selling, but shipping from California would be about the same as what I want for the manifold...