i finally need your help...please & thanks

[my1st69]

for some time now(2 years) she has been sittin. But parts are rolling in like crazy and I am ready to get to work. |Last night pulled the intake and pass side head to find one cylinder was half full of agua rusting up the joint. Can i just hit it with some 2000 grit and marvel mystery oil and call it a day before replaceing the head. ok next dilema. she has always ran and I took her off the road when she was running stroong with no problems majorly execpt the minor thing here and there. So when I turned on the headlamps before when I used to drive her they would come on until I clicked the highbeam button and the reg light would come on. I need help repairing this issue. and one oif my last concerns if the rear wire harnes fom plug to rear light I need one and am having trouble either finding it or the name it goes by. Thanks guys and gals