spitfire headers

Thanks for the input. I guess I should clarify. I ran a set on my last swinger (74) for a couple years before I swapped in the 440.
I saved them and they have been laying in my garage for about a decade.
I'm about to install them on a magnum 5.9 I intend to hop up over the next year or so in a 70 swinger.
I love the way they fit and even though the car came with a set of full length headers Im going to use these just for easy install and clearance.
Im curious who made any actual power with them and how they held up with constant use. I was unaware laysons was still offering this design. Im assuming since these are still in production by laysons they work ok.