How tight to set solid lifters

toolmanmike said
This is just a thought and these are hypothetical questions, what expands more at operating temps, valve stems and pushrods, or cylinder heads and blocks? Which 2 would effect valve lash the most at temp?

I’m pretty sure the Machinist handbook has the data to figure growth of different metals by temperature.

You have to consider the mass of the valve and pushrod compared to the mass of the block and heads. More mass equals more growth.

The pushrod and the exhaust valve don’t have the mass of the block or heads.

Valve lash opens up with heat. Simple as that.