Powerglide in 440 dart

I might be way off here but,

Since the gear drop of a 2 speed is similar to 1st and 2nd of a 727, couldn't just rear gear it so it just has same effective gear ratio as the 2 speed in 1st & 2nd and leaves 3rd as an kind of overdrive ?

Eg.. A 4.56 behind a 2 speed be similar as 2.94/3.23 behind a 727 in 1st & 2nd.