High Butterfly Prototype

[Matt Blast]

I have received an interesting project that I thought I would post. If anyone has seen anything that resembles these High Butterfly throttles please let me know.

The story goes that these throttles were attached to a display board. The current owner has had them for about 10 years and the prior owner bought them on the same display board and owned them for at least 20 years. That owner also bought them on the display board and owned them for an unknown period of time. Any history before that is unknown. The throttles have had moderate use as evidenced by the worn bushings and small grooves in the barrels. The throttle shafts are still in good shape and other wear areas are not that bad so they haven't been beat to death like a lot of them.

When I first looked them over I thought someone had modified a set of the 2.5 throttles, but I couldn't figure out how they would have resleeved them to 44mm on top and about 40mm on the bottom. They don't look resleeved. There are also some crude areas on the castings and even some differences from one throttle housing to the other. It soon became apparent that these are factory throttles, but what their application was in the day is unknown. They look like they were used for developmental purposes. The later throttles were improved in many ways. Were these the very first High Butterflies? Any thoughts?

Matt