firewolf

I am looking to buy a 1990 240sx but the auto tarnny is shot. I want a manual tranny. I searched for the swap info and found it. I have done swaps in old cars (1960's 1970's muscle cars) when i did these swaps the rear diff ratio for and auto is about 2.73 where a manual diff is about 3.27 or so. so in a 240sx does the diff need to be swapped also or is the gaer ratio the same in auto or manual. in new trucks the ratio is the same. does any one know the diff ratios?