Nissan P engine vs. P40

[Finder]

P40 engine power is 145 hp vs. 130 hp in P engine.
Whether the difference in power is due to using a different carb only?
Is there another engine elemnet affects the power difference?

If i will change only the carburetor will i get extra 15 hp?

[Sadam_Husain]

yeah theres more to it than just the carb mate, dunno the difference between those two motors but compression, air flow (valve size, porting, manifolds), cam lift and duration etc all affect HP and torque