Not hard at all. The ticket part is drilling the hole in a thin part of the block and being able to thread it.
A lot has been learned about cams since 1959. Check some of the milage grinds as they are perform in your normal driving range, off idle to 35000 or so. With a good mild build and the right gearing you'll be happy.
"I wonder if God created man because he was disappointed in the monkey?" Mark Twain
