thats because both the engine and the tank are on the left (passenger) side of the chassis. it would be more balanced if the engine wer ein the center, but thats impossible with shaft drive. the only thing i could recomend is the stagde D chassis. itl help out a bit but itll cost you $$$ what you can do is play with the preload on your springs to amke the engine side a bit tighter, therefore making up for the extra weight.

goodluck