From that site:
"Pound for pound, the 170, 200, and 250ci sixes make more torque than a small-block 302 or a 351 V-8 because they have six cylinders in a row on a common crankshaft for smooth application of firepower."
400 lb. 170" motor @ 150 ft. lbs. is more than 550 lb. 351" motor @ 350 ft. lbs? On what planet?
"Inline engines--be they four-, six-, or even eight-cylinder--apply power more smoothly and effectively on a long, common crankshaft than V-type engines."
Right - obviously, doubling the number of firing impulses (i.e., adding another bank of 4 cylinders) reduces smoothness.
He just doesn't understand the concept: "smoothness" refers to the shaking, vibration etc. as applied to the chassis through the mounts. It has NOTHING to do with crank rotational smoothness (power delivery), which is a function of the number of cylinders, flywheel/crank inertia and firing order, and is unrelated to the engine layout.
Single cylinder 500cc motor with 100 lb. flywheel is certainly "smoother" than a 4 cylinder with 10 lb. - you couldn't stall it if you wanted to.
Who writes this stuff, the gunk boy at Speedy's Pizza & Oil Change?