I did the same thing. I just used the drive shaft from the 87 toyota that my transmission came out of to put it in my 81. That way no flange swapping and no driveshaft shortening
![Thumbs Up :thumbs:](https://board.marlincrawler.com/Smileys/marlin/thumbs.gif)
But if you don't have one of those I'd swap flanges instead of trying to drill it
![My Two Cents :twocents:](https://board.marlincrawler.com/Smileys/marlin/twocents.gif)