Pretty sure you are asking about engine mounts for the Nelson 36c engine. I need a pair or two also. I have one N36c engine with the back plate with mounting forks, but this last run of new engines Henry did not have any of that method made.
The guys up in the northwest fly the N36c a lot so you may try an ad in the FlyingLines "Flying Flea Market"
http://flyinglines.org/fleamarket.htmlI have one set of the aluminum mounts I took to a local machinist to reproduce a few sets for me, I guess I need to go get them back as it has been over 6 months and I suspect he just never has the time to fit my very small project in
I am in no hurry as I do not think I will ever be good enough to compete....BUT if I needed a set I would start asking folks up in the northwest like
Tony Hubber
Jeff Rein
Don McKay
Ken Burdic
That link I sent above does have a forum you can join and while not a bunch of activity, a few of those I listed follow and post there
I expect Mike Londke will offer suggestions here in a bit