w126 sec Autogas?

Hello friends of the well-kept conversation, I have a few questions and look forward to your numerous answers. I am about to buy a sec. In numbers: EZ ́91, 4200 ccm, approx.200,000 km, etc…. My questions are: Does anyone have experience with car gas in this vehicle? Which system has been installed or is recommended? What does the conversion cost? (Room Hamburg, I would also take some km for a good offer) Which injection system is it with the model? Thank you in advance!!! And please no further discussion about the engine choice, Mercedsbee has convinced me completely 😉 Dear Greetings