I've seen alot of threads about putting a brake block on a 400ex and they always talk aabout buying a new lever and perch unless you like raddling and this is my solution, install the blocker remove the cable from the perch, without snipping it, just pull the rubber part back and take em out, nowyou hav the metal piece that was holding it together, put this piece in a vice and cut off all the material you don't need to fill the space on the perch