3:73 is my preferrence. I do question whether or not your 2004R is beefy enough. There are great mods for this tranny. In stock form it will not handle the Big Block as it sits. What are you willing to do for upgrades?. Pump alone whithout discussing the components rearward will have to be changed....and so on and so forth. A lot of successful drag racers beat this unit up all day long and have no failure.