That sounds very tall gearing to me .... where did you get your target ratio from?
Novak's instructions ....
http://www.teamnovak.com/download/in...pecgearing.pdf
..... suggest about 9:1 ..... now if they are as conservative as they seem to have been on the 5.5R I use it is likely to stand a couple of teeth higher but probably no more than say 8:1