The correct answer is "it depends" on what everything is made of. ALuminum heads for instance expand and contract at different rates than cast iron. Also, I disagree that "it changes very little" and here's why I disagree. I've had a LOT of engines through the years with solid lifters. They always and I mean ALWAYS get quieter when they warm up. That is.......with cast iron heads. I have very little experience with aluminum heads as I've never had the coin for such.
