[Musclecarkid]

The rear brake pressure valve was standard on all 70 Chevelles with factory front disc brakes. There were 2 designs available. Early 70 (actually 69) built cars used a valve with an "N" stamped on it. After 12-23-69 it was replaced with an "S" stamped valve. The "N" was rated at 250psi and the "S" was 400psi. Also all 70 Monte Carlos came with this pressure valve because they all had front disc brakes. The difference between the Camaro and Chevelle valves is the mounting bracket is reversed to allow a different mounting position. I have 5 of these dated from 260-9 "N", 022-0 "S", 023-0 "S", 079-0 "S", and 127-0 "S". I'm sure most other 1970 GM A-Body cars used this as well. Some early Camaros with AC and Disc Brakes or Big Blocks also may have one. All 70 Z/28 and T/A's had a simular valve bolted to the distribution/brake warning valve under the master cylinder. Most of the pressure valves I have are dated about 2-4 weeks before the build date of the vehicle.