Piddle-valve vs. Edge-orifice Lifters

[jackson]

Piddle-Valve ... OR ... Edge-Orifice Lifters? Dunno ... pleading ignorance here! Are they both "solid" lifters? Both "mechanical" lifters? Or is a piddle-valve simply an "anti pump up" hydraulic lifter? How do you tell the difference (pv-vs-eo) by looking at them? What are their differences in operating characteristics? Parts numbers for each from a single manufacturer? ... to compare? :confused: :confused: :confused:

[clem zahrobsky]

PV lifters have a internal valve to control the amount of oil that gets to the rocker arms. EO lifters control the oil because the hole to let the oil into the lifter is up high on the side of the lifter and only as the lifter goes up and down does any oil get into the lifter. the EO lifter cuts down on the oil passing thru about 20% and they should not be used unless you are using roller rocker arms. SBC can use them with stock springs because of the low tension of the stock SBC springs and only with the "drippers" in the valve covers. EO are hard to find but try speed pro(federal mogal) as they still had them 2/3 years ago. :chevy