Helping a friend build drivers from two bare frames he recently acquired. One is billed as a 1953, the other is unknown as to the year. Both have the tubular type shock mounts, but the difference is in how the levers at each end of the e-brake cross shaft are mounted. The '53 has two flat spots for the levers to slide on, but the other uses small teeth to grab the cross shaft and allows the levers to be mounted in two or three different spots. This lets you change the relationship between the lever and cross shaft by a few degrees if you should so desire. Does anyone know when Chevrolet made the change from the small teeth to the flats?