yeah-what he said, BUT, r-134 isn't as cold, so new cars have a bigger condenser and evaporator than old stuff. also different size metering orifaces. i recommend the 134, but remember the condenser is not as big as the later model stuff, so ya gotta use a fan that can move more air, or just live with what you have. in a pickup there should be no problem at all, but in a suburban, well, consider adding 2 units.
