Variable hydraulic lifters for 440 engine

Look up IQ52. He has done Dyno tests on changing lifters. I have changed each way depending on if I wanted more or less duration. The ramps are different so there is about a 20* difference. Hyd : more duration with a solid cam. Solids on a hydro cam : less duration. Has less lift now as u have lash. I believe u can get away with as little as .006 lash