Vintage Truck: 1951 Kenworth With 600 HP 2181 Cubic Inch Hall-Scott V12 – The World’s Most Powerful Factory Road Truck Of Its Time

Hall-Scott’s legendary 1090 cubic inch OHC six cylinder gas engines were the most powerful truck engines in their day, making up to 310 hp on butane (LPG) at a time when diesels were struggling to hit 150 hp. But even that wasn’t enough for this owner-operator of a tank hauler who wanted to tear up the Western mountain grades as fast or faster than coming down. So he requested that Kenworth build him a new truck with the mammoth 2181 cubic inch V12 from Hall-Scott, essentially two of those big 1090 cubic inch sixes on one crankcase, an engine designed for marine or industrial use. Kenworth had to lengthen the hood by a foot to accommodate it, but they made it happen.

In this shot we see the happy owner in the cab taking delivery of his new 600 horsepower hot rod Kenworth, along with a field rep from H-S (left) and a Kenworth sales rep. Unfortunately, the smiles didn’t last very long, but not for the truck’s lack of pulling power on those mountain grades. And it wasn’t the fuel bill either.

In the definitive—and only—book on the history of Hall Scott, there’s this picture with a caption that suggests they were considering offering the big OHC hemi-head V12 as a truck engine, but there’s nothing more in the text, including its hp rating. These V12s were rated at up to 900 hp, but that was with a supercharger, as used on some WW2 military high speed boat applications. I did find a reference to a caption for the top picture—but no longer available on the web—that stated this particular engine was rated at 600 hp, which sounds about right, given the 300 hp rating of the one-half sized six.

Torque would have been a staggering 1900 ft-lbs, based on double the 950 ft-lbs rating of the half-sized six.

This is the other photo in that book, taken at the same time as the top photo. The caption isn’t quite correct, as apparently Kenworth did the installation.

So why didn’t the owner’s smile last long? Apparently the rig went up in flames, and was a total write-off. No details were given. Hopefully it was only the tractor and not the load of fuel in the trailer(s).