Even the Mopar 3.09 is a bit much for anything over 3.55s, unless you have an engine with a really sucked out bottom end. I mean I really enjoy my 11/1 starter gear because with 185psi CCP, it's a dump-it-and-go deal; but really, it's way more starter than I need.
On the other hand, a 4/1 low gear is about perfect for 2.73s ............... and then, the .79 overdrive is good for 85mph ~2300
My questions are these;
will the BH for the big flywheel, still fit in the OPs tunnel?
What fork does it use? and
if longer than the one for the smaller BH, will it interfere with headers?
Does it use all the same Z-bar and anchors, etc?