ITS

I recently purchased a set of 91 s5 n/a , 9.7:1 rotors, excentric shaft, and counter weights that i intend on having balanced and sticking in my 86 13b n/a motor replacing the stock 9.4:1 asembly for my road course rx-7. Any body see any problems with this swap. I will change the main bearings but if the rotor bearings are with in tollerance i asume they will be fine.Any input or cautions I should know about?