That chart is close, but there is definitely some info on there that's questionable for some of the makes/models.
Is the car assembled? The easiest thing to do is measure. If you have a transmission yoke, push it all the way into the transmission, then pull it back out 1" and measure from the center of the u joint loop on the transmission yoke to the rear axle yoke. You're measuring from where the center of each u joint would be. This should be done with weight on the suspension, as that will change the measured length. Most folks use the center-center length, so you can use that dimension to either find the correct length driveshaft or to have one made or shortened.
As far as u-joint size, anything stock should be 7260 or 7290. 7260 is 2.125" across, 7290 is 2.625" across.
I just had a driveshaft shortened for the 8 3/4 swap on my Duster, the measured length was 49 1/4" c-c, which you will not find in that chart for a 340/833, 8 3/4 Duster/Demon.