Three to Four Speed Trans Swap Questions?

I bought an A body four speed out of a 69 Dart to put into my Duster. It currently has a 318 with a factory three speed on the floor. I was wondering how many of the original parts can be retained?

The clutch and pressure plate are fairly new and the flywheel was resurfaced by the previous owner. Will the new transmission just slide in place of the three speed?

What about my driveshaft? I will slide underneath later and measure the three speed, but I was hoping that someone would know the lengths of these two transmission. If I need to have the driveshaft shortened, I have a local truck shop that builds reasonably priced driveshafts.

Thanks to any manual experts that could chime in and help? Pics because EVERYONE loves pics.

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