| This is a stock used brake proportioning valve. Nissan calls it a NP valve and it gives these cars a 70/30 braking ratio. An ideal ratio is considered to be 55/45 but this can only be obtained with an adjustable valve. We do have those listed on our store if you're interested. The stock valve is located on the firewall below the throttle linkage on all z's from 73-78. The 280 zx uses the same exact valve and it is located on the frame rail below the battery. Last update 08/11 | 
