Snowman;

I have a 1971 Chevy Nova that is very similar in size to your Special. Take a look at the links at the bottom of my sig and check out the pictures of my car build. You can see what the 4bbl and manifold look like. Also see how you could do the exhaust from the Langdon's dual cast iron headers. Mine is a 250 as well with a Saginaw 4 speed that has a 3.11:1 1st gear.