Usually I put Sanderson on the street rods. Even at that, I have had to heat and pound a couple of them to get them to fit right.
This is so strange. The Headman that I put on the 1990 Corvette did not require the first modification. No dimpling, grinding, bending, cussing--they went straight on with zero hassles.
The Hookers I am fitting to the big block hate me. I have beat, pounded, and will be grinding on them today to get a good fit. In fact, it reminds me of the Sanderson headers I put on the last street rod.
However, I have talked to other people that will tell you a headman is a piece of junk, and hookers are perfect.
Who knows? My new outlook is to get a header in the painted version (cost less too). Test fit it on the car. When you know it fits, send it out to get coated. That way you don't end up dimpling a freshly coated or plated header.