Good evening Rick,
Thanks for your reply.
In fact I operated an avionic up grade on my FTB337G with also the installation of a STEC 55X that I bought at Genesys.
It seems that there is an stc for the STEC 55x for all 337 models except the FTB337G
It is approved for the FT337G and FT337GP so I think I will be able to get Genesys certification.
I am looking for an FTB337G owner with an STEC 55 x but they are rare.
Thank you for your kindness.
My pleasure
Alain