the shumacher headers, but they are only 1 5/8 inlets tri-y design.
i think with a 383/400/440 mild to mid build they are fine but when you start getting higher in the rpm band you will run into the small primary wall lol
they probably have the most clearance of any of the headers that will fit
on my 400 with eddie heads / schumacher headers all of the plug wires are at least 1/2" from headers
I have a set of 440 dusters headers for sale. I think they were custom made years ago. They came with a roller I purchased. Info in for sale thread. Can email or text pics.