Has anyone out there used Chevs of The Forties mandrel bent tube headers for the stovebolt engines? Any success/failure stories?

They are a popular, commonly used, made in Mexico(I think) tube header sold by many suppliers. Search for the best price. Also, if you can swing it, have them ceramic coated. They will last longer and look better. Check for flatness on the header plate though. Sometimes, but not always, they need a little masssaging.

I saw them for 150 at their site. Seems reasonable to me. Have you seen them any cheaper, and if so, under what brand name(s)?

Not a bad price. No brand names that I can think of,just different aftermarketers selling the same set. Clifford sells a different style, but they're $359!