I run the MP 528 cam and set the lash 20/22 cold. I run Stealth heads so the lash gets bigger as the engine warms up. I don't think I'd set the lash that tight with iron heads because the lash gets smaller with heat. 28/32 cold with iron heads would be around 26/30 with iron heads once it's warm and that's about what I have when the ally heads heat up.