Rear end mounting question

A stock early 340 makes about the same max torque as a stock early 318, and
the biggest tires that you can fit into the Dart tubs are 255s and,
the stock 4bbl-equipped 340 takes off in 2bbl mode,
so
unless you are running a manual trans, I wouldn't waste time pulling the 7.25 out, unless it had a really crappy gear ratio.
But, since I have one, I would install a SureGrip.