Pushrod length

for pushrod length if you are ordering, checkout utube vid "pushrod geometry for engines" by STRAUB. At half lift you want the right length that puts the rocker arm at a right (90 deg) angle to the valve stem for the most area under the curve. EDIT & you want your checking springs to be lighter than the hyd lifter springs as to not depress the lifter springs OR shim a pair of hyd lifters solid at your desired preload amt, say .015". I prefer that as less room for any slack anywhere giving you an incorrect reading.