I agree with Paul. I converted my '71 Imperial to R-134 in 1999. I still get between 36 and 40 degrees of cool air out of the dash vents, which is as good as you can ask for, especially here in the hot, humid South.Converting to R-134A or sticking with R-12 is a choice that one has to make. Here in Seattle, R-12 is about $200.00 per pound and MUST be installed by a professional. R-134A runs about $12.00 per pound, and can be installed at home, with the right tools and by following the directions.