Hello all, I have a 1987 Newburyport with Perkins t .3544 engine and would like to replace zincs as part of my routine maintenance to begin new season. Only problem is I just can't identify them. This is my 2nd season with the boat, moved her up from Annapolis last Spring (salt - brackish water) to Lake Ontario, fresh water. Have read from some sources there may be no zincs and would then have to tap some myself (with help from able mechanic). Any of you with same engine or knowledge of have advice? Thanks in advance for anticipated response.