do you mean dual 4's? you may want to stick with a single, say 750cfm, single plane manifold, and to get the 350-400, get a decent cam, a set of headders, and a good exhaust. You would save a lot of $$$ on gas by going with a single 4. As far as I know, there is no dual 4 intake for the 2V heads. There are a few options for the 4vs though. you could get a weind tunnel ram, and I think offy. made or still makes a simmilar thing to weiand. I think, but am not sure, edelbrock make a dual plane dual quad intake for the 4v, but I am not sure. If you have 2V's, you can get adaptor plates to mate a 4v intake to the 2v heads. If you went with the duals, get something like 500's, because you can have too much of a good thing!