as so often – the question is actually already in the topic. the five cylinders are known to be not gas-resistant – what do you have to do to convert to gas-resistant, how long could this take and how much could it cost? maybe someone even has a “rebuilder” at the start… or even better someone who already installs properly prepared motor components in exchange for the non-gas-resistant. however, it would be important that the engine number remains the same. I am grateful in advance for every hint.