i'm betting it is new lifter on an old cam shaft, never a good thing to do. Every camshaft manufacture will tell you to alway replace the cam and lifter together.
It kind of like putting in a new timing chain and not replacing the timing gears; you can do it, but it should be done because it isnt going to last too long.

 

See if you can capture the ticking noise with your cell phone and post it for us on Youtube.
Tall order I know..
I need to get my clunking sound onto yourube for you guys to hear.