Purple Shaft lash question.

I have never seen an engine with iron heads have the lash close up from cold to hot. I've seen some that opened up just .001-.002 but most open up .003-.004 and aluminum grows on average .006-.008.

They do close up, not sure how much. I always add .002 to the hot lash on initial startup and always have to tighten them up, hot and running.