By the end of the 50s, Hall-Scott’s legendary high-torque six cylinder gas engines were barely hanging on, as the heavy-duty trucking industry and buses embraced the superior economics of diesels, especially as turbocharged versions became increasingly available. Fire engines, especially the pumpers, which required maximum horsepower, were the last segment of the market left that continued to buy H-S engines. Their power-to-weight ratio was still unbeatable. That is, until the GMC gas V12 came along, and offered more power for significantly less money, thanks to it being essentially two mass-production GMC V6 engines in one block.
Here’s how it looked:
And it wasn’t just fire truck pumpers; irrigation pumpers also embraced the GMC V12 for the same reasons. H-S soldiered through the sixties (owned by Hercules by then), and built its last engines in 1970.