I don't know about later year parts fitting. But I have done many R-134 conversions with no problems. Done right it should be plenty cold. I have done several conversions using all R-12 parts and just changed the oil and freon to R134 by adding on the adapters you get from the auto parts store. I am A/C tech at a repair shop so it is easy for me because I have access to all the equipment to do the conversion. I have not done a 79 to 85 Toyota truck yet but plan to convert mine 85 4Runner soon. The last one I did was my friends 92 Camery last year and it's still working great.