Driveshaft on my 66 valiant fell off. Now what?

It should be about 51 1/2" long with the 7260 (2 1/8") u-joints. If you can't find one closer, I should have one also. The factory ones I've seen on that model are a "tube-in-tube" design with a sound deadener in between. I've replaced them with the solid tube design without a problem but if you're looking to keep it stock, that's what you're looking for. The yoke was extra long on that model also. Shipping from here might be an issue though......I'd have to check with UPS.