Transmission swap - Muncie M21 to New Process MY6

[Greg63]

I am wanting to get into an o.d. for my '63 and am thinking of swapping my M21 for an MY6.
The ratios for the Muncie are 2.20, 1.64, 1.28, 1.00
The ratios for the New Process are 3.09, 1.76, 1.00, 0.73
The two tranny's are physically identical, as are the input and output shaft sizes and splines so clutch swap and driveshaft work are not needed. Shifter location may be an issue.

I am looking for anyones experiences. Maybe someone here has done this swap already. Just looking for any other input.

Greg.