Buy a NEW not remanned compressor. Get the Hodyon (Hancock Industries) one. It does have stepped ports though. Hancock Ind was hire by GM to "reengineer" the R-4, per the Hodyon website. It is what I have on my car and is now in it's 3rd summer season. I am using Freeze-12, which we all know is a 134a and some other type blend.

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RRGrassi


70's Southern Pacific #5608 Fairmont A-4 MOW car

13 VW JSW 2.0 TDI 193K, Tuned with DPF and EGR Delete.

99 W210 E300 Turbo Diesel, chipped, DPF/Converter Delete. Still needs EGR Delete, 232K

90 Dodge D250 5.9 Cummins/5 speed. 400K

Gone and still missed...1982 w123 300D, 1991 w124 300D