I had a tune up about 3 months ago and just recently had my optispark replaced. The guy that replaced it noticed that thread on the block where the spark plug goes was kind of messed up and was causing and exhaust leak and loss of compression can this be fixed or am i screwed

 

It can be repaired with a heli-coil or thread insert, but is very difficult (if not impossible-depending on location) to do with the head on the engine.