Engine Analyzer Question/Lean vs Rich of Peak/Engine Longevity

[GJ Humphrey]

Hello 337 Devotees,

Can anyone help with the following?

I would like to install two Electronics International UBG-16 engine analyzers in my 73 T337G (pressurized.)

Owing to a paperwork error at the time Electronics International secured STCs for the UBG-16 in a host of airplanes, the STC for the C337 approves installation only in the C337 but not for the various models: C337B, C337G, etc., etc.

My mechanic, therefore, takes the position that the UBG-16 is not STC-ed for the T337G.

I found a 2003 thread on SOAP in which one contributor made the point, that the C337 and its various models were
Type Certificated without a EGT gauge (there was an "economizer" gauge available as an option) and, therefore, any EGT may be installed. These seems logical. Does anyone know whether this reasoning will hold water with the FAA?

However, the C337 was Type Certificated with a cyllinder head gauge. But the installation of an engine analyzer that incorporates a feature displaying cyllinder head temperatures does not replace the required cyllinder head gauge, rather it supplements that guage. Would this argument hold water with the FAA?

Bottom line: can I have the UBG-16 installed in conformance with FAA regs?

Lastly, has anyone had a UBG-16 or any other engine anlayzer installation approved under the Form 337 process?

Best regards,

Gordon