Denlasoul,
Yes, your Hp and Torque output from the engine remain the same in 1st through 5th gears.
I have not seen a Hp and Torque dyno curve for a C43, but typically the torque will rise pretty evenly till it peaks out at say 302 ft-lbs at 3300 rpm. Then the effiecency of the engine will drop off and so does the torque.
But because your engine is spinning faster it can continue to produce more Hp depending on how fast the torque curve drops off.
But remember that your engine has to overcome wind resistance and rolling resistance in the higher gears that use up more Hp, so the car can not accelerate as quickly.
If you want more info on this subject, let me know and I will go into more detail.
Jeff