Question about Mercury Racing motors?

[FormulaZR]

I think the fuel requirement of the 565 is the result of dynamic compression brought on by 4.25 stroke verses the 4.00. I am thinking the corresponding valve timing to go along with stroke, creates more cranking pressure than the 540. (did you follow that grads?)

Good point, I forgot to consider that.

You can bet your ass there is a matching cam change and possibly a intake throttle body change on the 540 to along with the exhaust manifold change from the 520.

I wonder. On the outside looking in, it's sometime hard for me to understand why the Mercury engines are so expensive. On the website/sellsheet, there is very little information provided. I'd love to know the composition of the rotating assembly, cam, and intake/TB specs.