390 quadrajet
???
What is that?
I agree on the headers - too noisy, only last a few years, clearance problems, not much power increase over split manifolds on a mild engine.
Cold air: most modern cars already have cold air (computer switched exterior vs. pre-heated air controlled by vacuum and throttle position), but the children rip it off and replace it with a piece of PCV and a fake K&N - for $300.
Yes, you should run exhaust heat to the manifold.
