Since you did not build the bottom end, did you check the cam to make sure it was degreed right? Did you do a compression and leak down test? Have you verified the timing pointer? Just some stuff that can really kill power. It may not set the world on fire with what you have but you should at least be able so spin the tires.
The gears are fine just not ideal if just a race car. The carb is fine also just maybe not ideal.
My 2 cents.
Curtis