I have a 1948 E3, while at a vintage tractor pull I noticed the other Co op's and Cockshutts had to add weight to get to 3600 pounds.  I barely squeaked in at 3594 with nothing added.  I started looking at the differences and noticed the front frame tubs on the other tractors were a lot thinner than mine.  Does anyone know the weight difference between the heavier tub and the thinner one.  Thanks in advance.   Steve