Looks like a made up 50 by someone who got hold of a #50 base casting and flywheel and fabricated the rest of it.
- Connecting rod is not Jensen.
- The cylinder even looks like it could be home machinist built.
- Water pump is definitely not Jensen.
- Block flange/governor valve is aluminum (should be nickel plated brass)
- Metal blocks supporting the cylinder also look like aluminum (should be nickel plated brass)
- Round head phillips screw was likely never used as a crank pin by Jensen.
- Governor gimbal looks correct (from what I can see of it)
- I like the addition of a crosshead guide oil cup.
- Clever adaptation using two #20 boilers.
Please correct me if any of you know different.