what rear would you go with

Well its alot of work but you can get the best of both worlds if you're willing to install an overdrive. I'm putting an A-518 overdrive behind a 440 for my Duster. The A-518 is basically a 727 with another planetary gearset added on which is a .69 OD. With 3.91 gears when you shift into OD it drops your final drive to 2.70. I got all the info I needed to do the intall right here on FABO and while talking to people I came across a deal on the JW ultra bell bell housing that will enable the A-518 to mate to the 440 (A-518 has a small block bell housing pattern and won't bolt to a big block without an adapter or the aftermarket bell housing. Its pretty involved but to me its well worth it.