Modify Elevator to Split Elevator

Larry, you are correct re the owner produced part. There should be no problem having the dwgs.etc. I remember hearing the late Bill O'Brien FAA Washington talking about the reg as he was pushing it thru the system - he wrote/reviised a number of regs with the field folks in mind. This issue is one of the reasons {vintage) the reg was written He stood in front of the audience and commented that the "owner" had to be involved in the process and with "tongue-in-cheek" he said the owner could be the final "QC inspector" in the process.. He was a great guy- very approachable - I had several interactions with him. The FAA has an award in his name. FWIW

if you go to the Ercoupe drawings 415-22001 film index A562 is assembly elevator.Film index A564, A565 and A566 show further details of construction. there is prior chatter on the mail archive section. The drawing for the split elevator is 415-200010 I believe. John Cooper said Skyport had the factory drawings , but Lynn Nelson said 'Yes John, It is possible to convert your straight elevator to the split one. The only pieces you use from the old one are the front beam (spar) and the end ribs. Everything else is different. I obtained a drawing several years ago and converted one. Since then, I have converted several airplanes, and I recommend buying one already made and rebuilding it vice trying to remake yours. I admit that I am slow, but making the ribs (only two are the same) and all of the skin pieces (six) takes me several days working all day.
If you do not have the tools to dimple the skins, and make the offset trailing edges it is really tough. (Unless of course you have access to or a friend in a metal working shop). Unfortunately, you cannot go to the local Sears Roebuck or hardware store and buy the tools and materials.
Please ensure you have approval prior to making the change. It took me several months to convince the local FAA FSDO that it could and should be done.

The legal part is not the problem. I work closely with a few designated engineering representatives (DER) and they told me if I can find any type of technical drawings that shows the material, skins and lay out of a split elevator they can create an 8130 form for me.

E models and later, as well as Forneys, Alons all had the split tail.