When you change the oil you need to use oil with zinc. I think the the brand is classic car or hot rod oil. I will look in the garage and let you know for sure.
They may not be able to do it til its done. They will need to send an appraiser out I'm sue.. You can still call and see what is required. They may have a appraiser or you may need to find one. I use Grundy. Had good good results with them.
I’m leaning this way. They did not try to hide anything. Had they caught the bad head prior, you would have had to buy one anyway. They noticed the temp issue and pulled the plug. I doubt they would risk there reputation buy screwing you on this. I kinda see the warranty thing. Someone could go...