I have a retro fit spray bar and needle valve assembly that can be used to upgrade the older engines with “clicker” style needle valves. This unit has the same 128 threads per inch as the Performance Needle Valve Assembly used in the TD 049.051 that I have sold for the past 15 years.
This means you can add this to your Medalion engines or any of the old OK Cubs, Wasps, Holland Hornents, etc. Then you can enjoy a needle that can handle the pressure of a bladder tank.
The needle has a friction seal like the one for the TD, so fuel flow is continuously adjustable. There is a lot of taper to the needle, so fine tuning is easy.
Unil I get this added to my web site, you can PM me and I will send you a jpeg of the unit.