Attached is a spreadsheet, that I originally posted in 2016, that is designed to give the user a starting point for selecting their camshaft. I wasn't able to edit the old one, so I reposted it here. The recommended duration is for intake. With Clevelands, and other engines, a longer duration may be desirable for the exhaust, depending on what the engine will be used for.
It also provides a starting point for torque convertor stall and carburetor size.
It's also fun to just play around with, to see what happens when the variables are changed.
If anyone sees anything that doesn't look right, or a value that seems unreasonable, please let me know.