a 2.73 geared ls1 will still move well. dont be fooled into think that big gears will help out that much when you enter the world of big convertors. a good friend of mine races his 2.73 geared 3700 lbs TA (he is a fatty) with the same convertor and runs mid 11s on a mild head and cam package. the last thing i would personally worry about is rearend gears.