i have 2 question that im not sure on my project and need help first is about the or pushrod i know that if you have roller rocker you dont need much oil and can go with or pushrod but i have stock rocker with xpz cam do i need the or pushrod with the stock rockers ?????
and for the is3 heads do they have longer valve like zzp stage 3 heads or the stock valve ?????(i will use stock rocker) do i will need rocker shim pedistal or i take the stocks rockers shim pedistal ????? thanks all

Best bet is to measure and or eyeball it. If you use a shim for the rockers you will want to run a longer pushrod.

For the XPZ, you will need to have the correct pushrods, as one is longer than the other.

thanks darkhorizon and do i need to use oil restricted pushrod or not ???? some people say with roller rockers and agressive camshaft and comp oer lifter it is recommended to use oil restricted pushrod because the roller rockers dont need much oil like stock rocker but i will use stock rockers with xpz comp oer lifter .