Converted a ’90 5.7 to R134. Should work for 88 and 89 as well.
High Pressure Switch for Recirc/fresh air valve: 4 Seasons (4S) 35972
Clutch Cycling Switch: 4S 36675
Accumulator: ACDelco 15-1676 GM Original Equipment Air Conditioning Accumulator (Amazon)
Condenser: 4S 40426 6mm Condenser w/ orifice tube
Compressor: 4S 58937 Compressor New /GM R4
Oil: ACDelco 15-118 Air Conditioning System PAG Oil - 16 oz (Amazon)
Fittings: MagiDeal AC Quick Couplers Connectors High Low Side Port Adapter Retrofit R12 to R134 (Amazon)
Flush: Johnsen's 6545-6 A/C Flush - 32 oz. (Amazon)
Flush Tool: Goplus A/C AC Air Conditioner System Flush Canister Gun Kit R134 R12 R22 R410 R404
Vac Pump: Harbor Freight or rent from auto zone.
O-rings: Santech MT2551 A/C System O-Ring and Gasket Kit (Amazon)
Evac R12 (shop), flush, install R134 fittings on old lineset. Drain oil from new compressor (if needed), Install new high pressure switch on compressor, install condenser (add 2oz oil), compressor (add 2 oz oil), accumulator (add 2 oz oil) and lineset. Vac and leak test. Add 1.8 lbs r134A. enjoy
High Pressure Switch for Recirc/fresh air valve: 4 Seasons (4S) 35972
Clutch Cycling Switch: 4S 36675
Accumulator: ACDelco 15-1676 GM Original Equipment Air Conditioning Accumulator (Amazon)
Condenser: 4S 40426 6mm Condenser w/ orifice tube
Compressor: 4S 58937 Compressor New /GM R4
Oil: ACDelco 15-118 Air Conditioning System PAG Oil - 16 oz (Amazon)
Fittings: MagiDeal AC Quick Couplers Connectors High Low Side Port Adapter Retrofit R12 to R134 (Amazon)
Flush: Johnsen's 6545-6 A/C Flush - 32 oz. (Amazon)
Flush Tool: Goplus A/C AC Air Conditioner System Flush Canister Gun Kit R134 R12 R22 R410 R404
Vac Pump: Harbor Freight or rent from auto zone.
O-rings: Santech MT2551 A/C System O-Ring and Gasket Kit (Amazon)
Evac R12 (shop), flush, install R134 fittings on old lineset. Drain oil from new compressor (if needed), Install new high pressure switch on compressor, install condenser (add 2oz oil), compressor (add 2 oz oil), accumulator (add 2 oz oil) and lineset. Vac and leak test. Add 1.8 lbs r134A. enjoy