The Dang Truck Engine Again

[drbarbara]

After I changed the truck carburator on my boat which has a Ford 302 off a truck for a Marine Holley, I got the carburator from a not very reputable carburetor place. The boat was not running well so I ended up taking the boat to a mechanic, had to have the carb rebuilt again and now the mechanic is telling me that the boat is running reasonably well considering the #7 cylinder has a significant (very significant) exhaust leak. He recommended to run the boat the way it is until the engine croaks and then either repower the boat or take it out to the back and put it out of it's misery. My question is how hard is it for a newbie to try to install new exhaust valve on the head.

Thanks again for helping the newbie.