Email Dave Crower at Crower cams. Or call the number on the top of the web page and ask for Dave Crower.
https://www.crower.com/
He made a custom grind cam for my ex's slant six when we rebuilt it a few years ago. It was a stock 64 slant with single exhaust and single barrel carb. He made a custom ground 260° duration with .490" lift. It ran great and she is happy with it.
Tell Dave what you plan to build, and he will make you a nice custom cam. He doesn't list any on his site as they are not high sellers, but he will be glad to make you one.