Tell me about truck ratings & a gasoline that never contained lead

Question:

For some time I’ve had a couple of questions about fuel and light duty trucks and I’ve never been able to find good answers to them.

First of all, why is a pickup referred to as a “half-ton”, “3/4-ton” or “one-ton.” Most “half-ton” pickups routinely have a capacity of 1500 lbs. or more, which is, of course, 3/4 of a ton! Is this a generic term that hails back to when a Model T pickup could haul 1000 pounds?

Second, there is a lot of discussion about unleaded fuel use in older cars. Suppose for a minute that I had bought a 1960 Cadillac brand-new and had never used anything but Amoco high test gas in it. Amoco, (now American), has never contained lead. Was there another additive they used to make up for the no-lead fuel? Thanks for any light you can shed on these questions and keep up the great work with Auto Restorer.

Answer:

I believe that you are correct about the pickup nomenclature dating way back to the good old days, when a half-ton truck was really rated to carry a half-ton payload, a 3/4-ton truck was rated to carry 3/4 of a ton, and so on. Nowadays, the designations are obviously not meant to be taken literally since nearly all pickups have a higher payload capacity than their name would seem to indicate.

The addition of tetraethyl lead to gasoline is not the end unto itself. As with all gas additives, lead serves specific purposes. The two most important of these is to raise the blended fuel’s knock resistance (as indicated by the octane number) and increase its lubricating properties. There are other ways that refineries can accomplish these same objectives and Amoco chose to use other additives, primarily certain aromatics, to do that.