Dutra ?

Those are correct statements. Also the number one runner could be blocked with a thin layer of cast iron. Easy to knockout with a screw driver. The rear manifold would hit the battery stud on the commonly used late '90 Dakota mini starter from the 5.2. The manifold needs to be ground down there.

They were not bolt on and go. But they work very well. Doug once said there was .10 difference from headers.