The bore size of a 3126 Cat engine varies depending on the model. Generally, most models have a cylinder bore of 4.02 inches (102 mm) and a stroke length of 5.20 inches (132 mm). This results in an overall displacement of 7.2 liters or 441 cubic inches for this particular engine series. As such, this makes it one of the larger engines offered by Caterpillar as far as displacement is concerned. The 3126 Cat was also manufactured with several different horsepower ratings, ranging from 175 to 425 HP at 2200 RPM and 480 to 550HP at 2100 RPM respectively - though these numbers may vary slightly depending on the specific model being used.