Low compression and lots of boost is how the older Cat equipment motors were built. They also had a glow cycle. The in line 6 cylinders produced more usable torque than the newer V-8's. The 633 C model scrapers had an in-line 6. When they came out with the 633 D's the old 6's would out work them in the hills. You could pull them down in the RPM range and build power back up. The V-8's you had to run more like the old 2 stroke Detroit's. Keep them near max RPM or the bottom would fall out of the power range.

Then there was the duel overhead cam V-12's in the 660's and triple 6's!