No kits. Most going to open differential switch the transmission out as well and customize a driveshaft to length. To keep the 3 on-the-tree you could go to a open tube Saginaw 3 speed.
Just an idea as an option, but it may not be practical, look at the construction of a 47-54 3/4 ton truck drivetrain.
2 piece driveshaft with a section closed and section open. It could be customized but the results would need to be rebalanced at a driveshaft shop.
In the end, it may be more cost effective to install an "Oakie Bushing" and seals in what you already have.
