There is a wealth of good information on this topic and related components on B3 Racing's website. The owner, Mike is a great guy to do business with, and is happy to help you get the optimal parts. His geometry correction kits are very reasonably priced too.

1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's
1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)