with the a500 or 518 you can't run OEM console shifter linkage (the girth gets in the way of the down rod). I solved that by using a B&M cable kit driven by the OEM shifter in my fury.
We had a GV in a crew duallie, we never gear split either, the 440 had TQ enough to never need it. We didn't pull huge loads but never really needed to shift out of OD up hills either.

Both my fury and Charger have .68 OD's (fury auto 3.91's, charger stick 4.10's) and the big OD drop is really nice for going 80mph down the freeway. The fury is stock cammed and turbos, so the OD kicking in around town isn't too bad, but the Charger has a 484 purple in it and I don't go to OD until 3000+ rpm or it's just a loping mess (and poor mpg).

When my fury was naturally aspirated it had B body headers on the 383 and they fit around the a500 with no issues at all.