quench vs no quench?

The two engines would not be built the same to reap any benefit from the quench effect. If you simply used a head gasket thickness to change the compression ratio, the quench distance would be negatively affected and the bonus goes with it. If an engine is designed, built, and tuned properly for quench, I'd expect it to be able to make a little more power for the same given amount of fuel over a non quench design, all else being similar. Quench makes the burn much more efficient. Capturing that efficiency and making use of it is up to the tuner.