decoding the rear end tag & no power question

okay I did try for over an hour to see if someone already posted about answers to the following questions. I don't know if the sn95 rear end tag decodes the same as the foxbody. what the stock gears should be in a 1995 mustang GT convertible or if there were a few options when it was ordered or built. never owned a V8 car that didn't have 373 or 410 gears. car idles fine but doesn't seem like it has a lot of power. did complete tune up on it. previous owner just did a fuel pump. haven't checked the timing yet though. recently moved and my toolbox with that in it is still an hour away at a friends. I can't even smoke the tires if I power break the car. car doesn't miss or break up. So any help you can give me will be greatly appreciated.