I ain't done it yet but way back when I studied up on it iirc you need to change to "barrier" type hoses/replace the receiver drier/replace the valve at the firewall/change the oil (type) in the compressor. Vacuum the system of course & I had heard that it (134) will cool satisfactorily but I guess that is subjective. I have no doubt that a larger condensor (in front of rad) and or evaporator (in or under dash) will up it's efficiency