The info Pope provided is right on the money.

When you start playing with the B and RB Mopars there is no such thing as an 'econo-stroker'. Besides the cost of any custom stroker crank, your also looking at pistons for a one year only engine (although with the fairly common 4" bore size and.playing wiht overbores you MIGHT find something with a wrist pin location that would work.

If you truely looking at building a "econo" motor I would look for a 413 which seemed to be a "magic number " for making torque for Chrysler and were used in Motor Homes and large trucks well past their replacement in passenger cars.