Which of these two 904's should I use?

I will be doing a 5.9 magnum swap into my '67 Dart GT ragtop. The engine setup is not finalized yet, but it will be primarily used for street cruising, some tire turning, and some road trip use. I am guessing somewhere near 300 or a little better for torque and HP numbers. Rear end will be an 8-3/4 with 3.55 sure grip.

I have the following 904 transmissions to choose from:

1967, which is still in the car attached to the factory 273. Or, I also have a clean 1968 904.

Are they identical, or is one a better choice than the other for my application?

Thanks for the advice!