IF your used cam does not have worn lobes, you just have to break the new lifters in (so it's possible to wipe lobes if the break-in fails, I suppose). On the other hand, a new cam/lifter set isn't that expensive...
The problem is in trying to put used lifters on a new cam - never do that.
Big block A-bodies are a perfect example of the 90-90 Rule: The first 90% of the project takes 90% of the allotted time/money. And the final 10% takes the other 90% of the time/money! BTDT :D
