I just put a new cam in my Falcon six to get rid of the 280 duration stick that was in it (automatic also). I bought a Comp Cams 252 and new lifters. One of the new lifters would not slide all the way down the bore, it kind of got stuck, so I used a magnet and a pick and got it back. On closer inspection, there is a crack in top edge and has allowed the upper part of the lifter to expand just enough to not slip in, which is good, because otherwise I would have unknowingly installed a bad new lifter. Since I bought these parts mail order, I was kind of frustrated, so I put one of the old lifters in. I know this is not recommended, but they have less than 5k miles on them, and I put a straightedge on the base and it was still flat. I haven't put the engine back in the car, but I did put the head back on. Now that I'm back in the house, I'm having second thoughts, and if I get enough "You idiot, you should pull the head back off" responses, then I'll do it, but sort of just hoping for a few "I've done that, don't lose any sleep over it" responses.
Put a new one in. If nothing else for peace of mind. If you don't, it will probably bite you on the *** and you could lose the cam to boot! Usually you always use new lifters, as they get a wear pattern to the individual lobe.
Thats a no-no ..... Once a cam is broken in the lifers are mated You can put new lifters on a used cam..... But NEVER a used lifer on a new cam Unless You want to change it again next week Tony
You mite as well use all used litters . Will you be happy with the car if 5 cylinders run good? Change it