new lazy lifter....
solids are not loud. My Ford 312 had them and you could no even hear them on start up. Idle was butter smooth as this Fairlane 500 was a high end sedan back in the day. My 273-4 had them and they were not loud, my 6 has them and they are not even noticeable. If the lifter continues to clatter, take it apart again an replace the metering disk/check valve from another like lifter. No need to replace the lifter body itself. Usually a loud lifter is a hung up check valve as the machining nowadays on a Johnson piston and body are very automated and very precise. I drove a 302 that had a loud 'lifter', it wasnt the lifter it was the flat nosed cam lobe. preload on a mechanical rocker hydro is touching plus ~1/2 turn. Make sure the rocker is good too, not wallowed out on the shaft.