[HotRodmicky]

pop up? high flow and high compression.......

in that case it`s a 1/8 stroke difference. 1/8 :2 = 1/16 higher in the head
If really necessary you can redome any head 1/16 ...
Sharp allows a lot more

I used the pop up therm more a joke as 1 /16 is not a real pop up...

Ross has 4.125 pistions in stock, but 4.375 are special order.

A stock head you can shave 1/16 off and still have enough clearence.
Recut the valve pockets and you are fine.

Michael