Sea Rider, working with stuff run in the salt, I get in to this situation on occasion (too often actually). Early on, I USED to try and fix them. Have been the Helicoil route on a head bolt a few times, with mixed results (tried using the head for a drill guide trick too). I got tired of rolling the dice on the finished product AND all the tedius prep work/coil install. I can swap out an entire block nearly as quickly. That would be my advice, especially when working on a smaller motor. Go out on the used parts market, find a block at a reasonable price, and just swap it out. Many times you can find "fresh water only" part that's are all cleaned up and ready to go with a very reasonable price. -Al