New motor, sounds awful?

Pushrods are brand new.
No sign of contact between rockers and the baffles.
We fired her up tonight, and held her at decent revs.
The noise didn't go away. I took a vid on my phone, but I'm a cabbage with technology. So I might have to get a mate to help me upload it, and post it online.
It sounds very clacky. Which leads me to believe that it's the lifters not pumping up.
I'll have to try get the video up.