[When you adjust your valves do as 66fs but instead of adding .002 to the cold tolerances you`ll want to subtract it. ] No this is incorrect. As the engine heats up everything expands and your gaps shrink, even more on the exhaust valves.
I apologize, 66fs is correct with your application, iron head/iron block. I haven`t worked with that combo and a solid cam for a while. The clearances are going to be different for every engine based a lot on block and head material. I find on my aluminum head 440 the hot/cold clearance varies about .007 so for example, if I want my exhaust lash at .019 hot, I set it at .012 cold. Probably the best way to set the lash would be to set it with .002 added to the factory specs (as 66fs said) and then run the engine until it`s hot (it`ll likely be noisy) and then measure again while the engine is still hot to see how close you are to the proper clearances. Here`s a link to a cam site to help you. http://www.cranecams.com/?show=faq&id=4