You really need to use an adjustable checking pushrod and get the correct length pushrods. Not sure which rocker arms you have, but the ones that oil the pushrod through the adjuster have a very limited amount of adjustment, usually from all the way up to two turns down where you would set the adjuster one turn down and adjust the checking pushrod for the proper lash or pre-load (if hydraulic.) The rockers that oil the pushrod with a hole to the edge of the adjuster may be a bit more forgiving in adjustment range?