Problems installing new pushrods!

NITROTRIP said
Watch your
pushrods at the rocker arm. If they move closer to the rocker shaft and away as they open and close the valve they are to
long or to short. They need to go straight up and down for correct geometry. Think about it, if the top of the rod is moving
back and forth that is why you bend/break pushrods. Worst case can even break the rocker at the shaft.

Rick
Click to expand...
This has got to be the simplest and best advice ever given (here) for pushrod length. However I would not do it with the engine running. You can easily see this motion by turning over the engine with the starter. Or even by measuring from a reference point while tuning the engine by hand... which is how I'd do it.