I believe you are right that the 235 was used in big trucks before it was used elsewhere. But since this motor is in a 50+ year old truck, you should check the casting and serial numbers to be sure you know what you have.
My '52 has a stock looking motor in it, but my '51 1-1/2 ton has a later motor in it. I've not yet checked numbers to see if they are what I think...