440 head noise. Perpetual problems. Problem solved

It sounds like it's coming from the middle. I read other places that it might be a bad lifter. How do I check the lifters. It sounds like a metal can with a hand full of rocks in it being tumbled around but when I put it in drive or reverse it all but stops. We have a road run here and would love to take it out but no way would I drive it like this.