If your others are early 60's Freightliner cabovers, they are quite likely Athearn. If so they will be scale. Your new one may also be scale if it is a 1940's IH conventional. My dad was in the wholesale nursery business from 1949 to 1955. He had a 1952 GMC diesel powered by a 4-53 diesel. My uncle at the same time in the same business had a BIG GMC tractor. I think his had a 6-71 in it. My uncle's tractor would dwarf my dad's, but both would look small next to today's trucks. In 1940, semi trailers were probably limited to 35 feet in length max, and max vehicle length would have been 55 feet. In the late 50's or early 60's the max length was increased to 65' except for the states that bordered the Missippi River. I saw one instance in the 70's when a truck driver working for a fleet I worked for was stopped in Misouri, and had to have someone come out with a torch, remove the rubber dock bumper from the back of the trailer and then cut some of the steel off the trailer because it was 3" over 55 feet! In the 80's or early 90's the law changed to set national standards and any state that refused to go along would loose all federal highway funds. At that time the maximum overall length of a truck was set at 65 feet, and max weight was 80,000# gross. In the 90's the law was changed again to the current standard, which is that trailer length cannot be more than 53 feet, but overall length of the truck is either not restricted, or it is something like 100 feet. That is why class 1 cabovers are no longer being built. By the way that 4-51 detroit probably put out 100hp. The 6-71 would put out 230 hp. Todays trucks make in excess of 400-500hp, and some even go up to 650hp. It is probably like comparing a Sd9 to a Sd70mac.
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