P-63 (?) Airacobra/Kingcobra power question

A question for the physics-minded among us, or for anyone who just has
the answer.

I have heard the Airacobra was underpowered and that got me to
thinking;
Does having an engine at the middle of the fuselage (in any plane for
that matter, like the XP-58) and connected by a long shaft contribute
to a loss of power delivered to the propeller? In other words; would
there be more power delivered the closer the engine is to the prop?
Does the shaft "eat up" power in any way? I am a mechanic and pilot
and fairly knowlegable about a/c physics & aerodynamics but this has
me stumped.

Thanks in advance for your ponderings and/or solution!

Ricky