Sounds like good idea, no sense in letting that carb go to waste. I did a lock up converter and use a switch for locking up. I can lock up in 3rd gear which is nice when driving at about 30-50 mph. At the track using the nitrous I lock it up in 3rd gear when I get to around 5200 rpm and it drops the rpm a couple hundred or so. The 2004r will at least have a lower 1st gear than your 350 trans and this will help with your highway gear until you get the rear end dealt with. Good luck with the carb would like to see it work like it should, it will rock with the 373 or so gear, with 2004r go with 411.