Where is the blow out valve located on a z31?

There is no BOV in the z31 because of the 6-8psi stock. There is an emergency pop off valve located on the intake manifold. The round thing that sticks out. That is to keep the engine from overboosting. Take this off if you are going to add boost. On a stock z31 don't go over 12psi without an intercooler. john.

The z31 has an internal wastegate that starts to open around 3psi so there is little chance you will overboost.