"That's very interesting. I take it you are using a counterbalanced crank as 16 pounds is quite light?" updraught
Yes, you are correct. The crank is counter-balanced. With or without counterweights, however, the principle in going around corners would be the same. Those added weights to the crankshaft would not be enough to offset the lost 65 pound flywheel in maintaining inertia and torque. I don't always need to downshift from third to second while going around corners, but often enough that it is noticeable. The other side of the coin is that the light flywheel allows the engine to slow down quicker to match the transmission RPMs so that a smooth downshift at speed is possible. It does take a short learning curve to master this technique, but it certainly comes in handy! As I say, an aluminum flywheel in a Model A is not everyone's cup of tea. But after you have driven a Model A with such a flywheel and then get into one with the original boat anchor flywheel, you'll wonder what's wrong with the engine in the second car because it will feel so sluggish by comparison!
Marshall