How to change GW from 1400 to 1450 on Forney F1?

The Airworthiness Specs file 787 (in the files on the EOC site) gives the modifications needed to convert an F1 to a F1A with the 1450# GW. The info is in Note 5 on the last page of the specifications. The trick will be to get and install these parts. Since they are part of the Airworthiness specs, an A&P will have confirm whether paperwork other than a logbook entry is needed to install the parts and increase GW (the latter of course will require a new W&B calculation and form.)

I just sent Matt Gunsch the paperwork Forney did to up to 1450 lbs. for the FAA. I am sure he has not had time to put it into a down loan state yet. Maybe talk him to see about a copy. Find a DAR who may help with a 337?.

I have a Forney
 F1 #5714 that has a gross weight of 1400. the Forney F1A has a GW of 1450. What can I do to qualify for the 1450? Would help to stay legal with a passenger. Thanks!