I have a 1955 331 that makes what I think is a lifter noise when it's warm. The car had a solid lifter cam in it that was a little big for the street so I bought a hydraulic cam, lifters, adjustable push rods and matched springs from hot heads about two years ago. I can't remember the box color. The heads were rebuilt also. The bottom end had the 30 over stamps on the pistons and I could still see honing marks in the cylinders so I pulled a main off and the bearings looked good so I left the bottom end alone. I read the search posts for hemi lifter noise and I thought it was the rockers. I pulled out the rocker end caps and cleaned everything out with a bottle type brush and marvel oil and a can of spray sea foam. I thought they were clean but the lifter noise remains. I tried 10w30,15w40,20w50 no change. I now have a 5 gallon bucket of oil in the garage. I ran it with no valve covers on to watch the oil flow and the passenger side doesn't have the same amount of oil as the driver side, but it is getting oil. I called Bob from hot heads and he said I have a few dirty lifters? I push on the rockers when it's running and the noise doesn't change. Any other Ideas?