[MikeK]

There is an extreme advantage I see to the Burtz 5 main crank. The counterweighting is 100%, vs. 60% for the press-on overhang Ford B crank, 40% for the forged countered B, and 40% or less for weld-on A crank weights. Additionally, the weights are equal on both sides of each throw. With a three main crank the weights are all extremely biased on one side, imparting torsional stress at the critical throw radii points that lead to fractures. The crank weighs ~90 lbs vs 50+ for a countered A or B. The mass is where it belongs- in the crank rather than in a heavy rear flywheel.

In addition to the greatly reduced crank harmonics, the material itself, cast nodular/ductile iron is inherently much more absorptive of vibration than a steel forging. The only disadvantage is the material is only good to 400 horsepower or so, hardly a problem for an A engine. Also, the Burtz design will use an actual rear seal, not the slinger or one of the other band-aids found on a stock A.