how strong is the 8 3/4 #741 case?

RLF Cuda said
This article from Speedway Motors on U-Joints give useful information about that weak link in the drivetrain.
U-Joint Identification | Types of U-Joints Explained (speedwaymotors.com)

I'm getting off topic here, but the guy behind the New Mind youtube channel does great videos. Here's a recent video he did on the history of driveshafts and the various joints they use. But I'm sure if we asked him he'd say the 741 case is fine :D