I had a sparkplug blow out of the cylinder head and ripped the threads out of the head which required a complete head replacement. I have been to other forums and have found that this is a fairly common problem. Ford has never issued a recall on the heads, even though it appears to be a manufactures defect(not enough threads in the head to hold the plugs in place). I am wondering if anyone else has experienced this problem and did Ford offer any help paying for the repairs. This engine is in a Georgetown 325S class A motorhome.