OKAY after some "engineering estimations" I've come up with the rears will lock up on dry asphalt at 120-ish pounds of pedal effort at about 2.75-3 inches of pedal travel (from top most position, your mileage will vary depending on shoe gap, brake lines, ect...). This is assuming a stock drum drum system. To the well calibrated right foot of you guys driving stock trucks does this seem "in the ball park"? These calcs were done assuming no proportioning valve.
