I have a 2003 f150 with a 4.6. I was wondering if there was another exhaust manifold from another year that flows better. Is the 5.4 any better than the 4.6 and would it boly up. I have sen tbird manifolds pictures that look like they were better than what I have. Iknow a header would be better but funds a limited and I will be doing good to get better exhaust from the cats back.