Oh no! Driveshaft too long?! - Unfortunately, I ran into some serious problems getting the driveshaft to fit. It turns out the issue was the slip yoke was missing a custom counterbore which D&D had added to their Ford 31 spline yoke which came with my T56 Magnum. However, the driveshaft already inlcluded a much better slip yoke, and QA1 mentioned that the equivalent cast piece's weight made balancing difficult-to-impossible, so I did not use it.