With the price of used 5.7 hemis coming down in price at the salvage yards, you could modernize the car for about the same dollars (possibly less) than the price of a good 440 and tranny combo. Street and Performance has just about everything you would need to do the install and Hooker is making the headers now.
Turn the key and head down the highway on the Power Tour. Power, reliability and decent fuel mileage as a bonus and it's a hemi.
Just a suggestion.