It sounds to me you are putting the emphasis on "cracked Magnum heads will be used".
Now almost everybody else will just dispose of them (baah, they're cracked...), but you seem to have a recipe up your sleeve to use them anyway...
Interested.
I didn't really mean to put emphasis on the cracked aspect just that they are the only heads I have ATM. Seats and some Fluidweld will take care of the cracks in most cases. J.Rob