Maxum 1800 Sr V6 4.3 Lx Has Engine Problem

I have for sale my 1993 Maxum sr bowrider which i have owned since new it has a v6 mercruiser 4.3 lx which has always been serviced and winterised regularly but unfortunately 2 seasons ago the head gasket went so i fitted a reoned head with new valves and push rod ,new exhaust manifold and risers and all new HT leads ,but when it fired up it had a tapping sound which wasn't there before at this point I gave up and have just left it until now,so it could anything but if you assume the worse is a engine rebuild and bid that way/This boat has served my family well over the years it come with a lovely american easy load galvanised trailer in great condition ,a full overall cover it also has full bimini top with side windows.As you can see from pictures it is still a nice looking boat clean and tidy it seats about 7 people and has no trouble pulling skiers up, there are a couple of seats with small splits in as you can see in pics. Also trim switch doesn't work but trim motor works find must be corrosion in switch also as you can see in pics the red strip around the boat is begging to fade and has a few age related scuffs.I have have been as honest as I can about this boat but I think if you have the time and skill to fix engine it will give you lots of fun my family will be sorry to see it go . Buyer must pay 200 pounds deposit at end of auction as I dont what any time wasters