which refrigerant?

[gmachinz]

Engine, you won't have as much of an issue with the retro-fit as you think. I've performed many R134 retro-fits and the biggest difference is that R134 moves at a slightly higher pressure than R12 did which means less time for heat transfer through the condensor which is why they make the note about using an electric fan. The Mark VIII is more than up to the task and just so you know, we will be testing a new AC probe that will measure liquid line temperature and adjust fan speed using that info along with engine temperature, too. Fill your system to 90% capacity and you'll be fine. Oh, and replace/clean your expansion valve, too. -Jabin