Some of you may have noticed a brief mention by SEL69L that he's had a 450 differential fitted to his car. This step was recommended by a friend of his that's quite heavily into American muscle cars, and he sort of specializes in making cars go 'harder'. That of course was the motive of fitting the 450 diff to David's car, but it was also suggested that the whole drivetrain would run more efficiently. Less torque converter slippage, more definite top gear engagement, it should run more...