I have a 1980 F150 Ranger and I plan on building a 400 stoker for it. I have a stock C6 and a stock 9" with 31 splined , 300 ratio. My new engine will be used for everyday driving and occasional towing. I guess my question would be, are the existing gear ratios going to work for the extra HP and Torque. (approx. 375hp & 450tq). Any suggestions or comments would be appreciated.