These were purchased 15 years ago as a suggestion to fix a problem we were having on a big lift roller hemi. The engine builder said this would fix the the problem were were having with ruining the ball adjuster on the rocker arms. I did not buy that fix and called Tim Banning and solved the problem. It was not lifters. The motor still has the originals installed. I was hoping that someone would recognize these as really good lifters from the old days when we could still get quality parts. They were expensive.