Quick and easy way of testing the rod length adjustment (from Jegs site);

Use the following procedure to check the push rod adjustment.
CAUTION: Wear protective goggles when performing the following procedure! Brake fluid may erupt from the master cylinder with sufficient force to cause personal injury.
1. Remove the master cylinder reservoir cap or cover.
2. While an assistant slightly depresses the brake pedal, watch for fluid to erupt in the reservoir when the pedal is depressed 3/8” to 1/2”. This indicates correct push rod length. On dual system master cylinder, fluid may spurt only from the front reservoir.
3. If the pedal travels more than 1/2” before master cylinder fluid erupts, the push rod is too short. If nothing happens no matter how far the pedal is depressed, the push rod is probably too long.