FAA Form 337. Mitchell instruments mod.

[GMPoland]

Have any of our fellow skymaster owners completed the conversion from the factory guages to the Mitchell instrument cluster for engine instruments as depicted in the link on this website?
If so, May I have a copy of the complete form 337 for the approval process to submit to my FSDO. I have already purchased the guages and sending units and it looks like a relatively simple mod. IA want to get approval from the FSDO first. A detailed search of FAA,s form 337 did not reveal any had been submitted for the Skymaster. At least not available online.
If you have this mod and the Mitchell instruments cluster please reply with a tail number. I can search the FAA website and get the 337 for tail numbers only. Local FSDO attempted but need to narrow search down. Thanks

GMPoland. N137MC.

Mitchell instruments was kind enough to furnish the documents and a special thanks to Jim Stack as well.
On with the work now! GMPoland