yup, it is a lot of trouble to put a used on in there that will probably fail.
this is not a part you want to go used with. the fact that you are asking for a used cam makes me wonder how you know you need a new cam to begin with?
you aren't going to get a cam in there cheap. you will also need: front cover gasket, valley pan gasket, a can or 2 of right stuff, lifters, new gear and chain if you go with marks set up, oil and antifreeze.
marks kit at around $500 is cheaper than buying everything oem.