Any one increased 5th gear ratio on a big block 5 speed by substituting the two 5th gears with the higher ratio ones from the Quota 1100, yes they fit and It has been done and works but I don't know anyone that has done it that I can ask, the ratio is increased by 2 1/2 percent however I don't believe that equates to KPH ? and I would like to know what advantage obtained is as in lower RPM when cruising. I don't think it is 2 1/2 per cent , I have just had my main shaft separate so have the transmission down while I repair it and with the shaft separating it has forced 5th gear into the bearing requiring the two gears to be replaced so seems a good time to go down this path as Im already up for two gears and the only other item I require is to change my 6 dog engagement ring to a 5 dog. Any one have any knowledge in this area (Charlie/Peter ??) chime in if you know anything Thanks Bill.