From 1974 – 1976 General Motors used a VIR (valves in receiver) on their A/C systems. The VIR eliminator will eliminate the original VIR to allow the A/C to use R-134a refrigerant. The kit includes all the necessary parts to convert your VIR to a CCOT (cycling clutch orifice tube) system. This kit requires the suction (low) side hose to have a new fitting crimped onto the existing line. The kit includes all the necessary parts to connect to all the existing lines, the oil line from the evaporator will connect to the block provided A simplified version of the instructions are below:
Remove all the lines from the original VIR.
Screw orifice adapter block onto evaporator inlet fitting
Reattach original lines
Cut off old suction hose fitting, and crimp new fitting to hose
Attach new hose fitting to the accumulator
Screw new clutch cycling switch to accumulator
Disconnect clutch coil wire from coil and route to cycling switch. Make a new lead from the open terminal on the switch, back to compressor
These directions cover the installation of the vir eliminator, the system has to have the correct oil added, and an evacuation and charge also.

Click here for the Instructions.