electrolysis???

Here's a question regarding electrolysis on my 91CE, (that I have not seen addressed yet on this forum). I had my head gasket replaced by an independent about 4 years ago. At the time he had showed me on the block & head some electrolysis damage to these surfaces. He sent the head out for repairs & used some sort of "epoxy" on the block & smoothed it out. The damage I assume was caused because some previous "bonehead" had not flushed the coolant enough, and or did not use MB antifreeze, is this right?. Of course I feel that this epoxy fix was kind of a mickey mouse way of fixing the block, but he said that this was fairly common & was all he could do, (other than get a new block). Has anybody else ever heard of having this problem?, if so, how was it solved??. I had considered selling the car at the time because I figured it would just get worse. (The mechanic did say that it would not last forever), somehow, I understand that he was just trying to cover his butt.
Well, I have kept the car (and am very glad I did, I love this car), however my local dealer has informed me that the head gasket is leaking again!!, oh goodie!!. I do not want to sell the car, but is my only option a new engine??, they say that it will probably only leak oil (no big deal), & not water. The damage was on the passanger side toward the front of the engine, I guess this is where most of them leak. One can not shave the block, ( I forget what the hotrodders call this),any ideas from the pros would be greatly appreciated, as this has me concerned about the long haul with this car.
I know this is getting long, but one last thing. How about putting a sacrificial Zinc in the cooling system (just like we do in our boats for elecrolysis), to late for me, but might help someone out there. Thanks for any replies
scotty