Using a tool manufactured by Miller Detroit c-3648, The range measurement from the unaltered valve spring seat pad to the tip of the valve stem is; 2.125" to 2.090".
Well, I've measure them to 2.126" which is a tiny bit tall so in theory I could shim them 0.035 and keep valvetrain geometry if 2.090" is whithin tolerance.
Then I shuold get about 0.075 preload, a little bit much but a bit closer and then I don't need to change pushrods.
What do you think about that?