who runs lash caps....

[Lavey Huffer]

who runs lash caps....pro's ,con's

[WannabeRacing]

Con's- A bit heavier. When you have a problem with your valvetrain, and something comes un-glued, one more part to fish out of the valley. And depending on your locks, you may need to "customize" to get it to sit down just right.
Pro's, depending on your particlar rocker arm, some actually get better geometry with a lash cap. It also disperses the load over the rop of the valve equally, and if perfect geometry is not the ultimate goal, it gives you lots more room for travel on the roller tip. Titanium valves without hardened tips have to be run with lash caps.
With a full jesel/T&D shaft set-up, sometimes getting the geometry perfect with the added height can give fits, but with stud mounted, you very rarely will have issues.
Some of my engines have them, and some do not.
If your roller tip is anywhere close to the edge of the valve on total travel, then run a cap.