Short Development in a Musso Sport Pick Up

My problem is that the fifth march only has a difference of 200 laps compared to the fourth, so that the development is very short and spends a lot. I would like to know if you can change the fifth piñon for another Musso that takes it longer. If yes, what Musso takes it? THANK YOU

If it can be, but there to perform some calculations to obtain the attack and primitive diameter, to be able to enhance the calculation of the diameter and the amount of teeth, it is not easy at all, but I do not think that it comes from factory to the factory that another problem, when you handle it on the road and pass from fourth to quiet and accelerate it in fifth you feel that the vehicle increases the revolutions but the speed is the speed?

The clutch does not skate, the problem is that the piñon of the fourth and the fifth are very similar in development only 200 turns the engine. I think in the normal Musso the development of the fifth is greater, but I am not sure. If so, I would like to know if I can exchange it as is something else. ALL THE BEST. THANK YOU