340 issue after camshaft change

You don't have to pump up hydrualic lifters but as Kim stated, Instead of turning the puhsrod to feel for zero lash, you move the pushrod up and down until there's zero lash then set preload .
I put hydraulics in my old Harley and you install with no oil and slowly screw in until the lifter is bottomed out and then back out a turn. Totally different concept. (Not For Cars)