i found out my valves in my heads are .100 longer then stock, what causes valves to be needing to be longer then stock? and if its just a case of fitment for springs or whatever, then does that usually indicate the pushrods are gonna need to be aprox .100 shorter then stock? i do know i gotta check with a measurement tool i just wanna be sure i know the basic facts.

 

Sometimes it will allow a bit more lift (area for air to flow through) if springs allow it and there is no bottoming of the retainer. Other times guys want to run a taller/more agressive cam profile which needs to have a taller sp[ring to thwart coil bind so a longer valve is used combined with a taller/heavier spring rate to allow more valve travel and thus allowing more air through.

Everything will hinge on the complete valvetrain set-up/components for proper geometry. One cannot assume "I have a .100 longer valve so I need a .100 shorter pushrod" checking is the only way to see what you need.

 

i know checking is the only way, but it makes sense right a longer valve means your probably gonna need a shorter pushrod.