what is the normal warranty period to replace head with used head, head resurfaced and valves machined. All new gaskets. The car originally went into shop on 07-07-04 tohave head repaired replaced gaskets 1 year warranty on head & spark plug holes only. paid $1400. and havve had problems up until they replaced the head the last time he said the warranty would be 3mos or 3000 miles. He said they never repaired head last time they just fixed spark plug holes. my invoice said repair but is it only 3mos 3000miles for the last repair? isthat right?