The original Baby Ace was manufactured in kit form in 1931 by Corben Aircraft Company established in 1923, after having first flown in 1929, and designed by O. G. Corben. It resembled a Heath Parasol with "N" wing struts. Six Corben Baby Aces were factory-built starting in 1929, the rest kit built by amateur builders.
In 1953 Paul Poberezny and S. J. Dzik completely redesigned the Corben Baby Ace with intention of offering it in kit form. The landing gear was changed to a simpler design fastened only to the lower fuselage. The wing struts were changed to parallel struts from the "N" strut original version. Wing span was increased, as was fuselage length. The redesigned model C rights were then sold to Cliff Ducharme. A couple hundred were built.
The single place parasol wing aircraft was again redesigned as the model D.
The model D prototype first flew on 15 November 1956. Many authorized refinements of the basic design exist, and it is difficult to enumerate the changes, as Salmson 45 initially, and Continental A65, A85, C65 or C85 engines mainly later were used. Construction was welded steel tube fuselage and tail, fabric covered with braced wooden wing, fabric covered. Taildragger gear was fixed.
The two-seat Junior Ace was redesigned as the Junior Ace model E. Edwin Jacob acquired the company in 1961. He then sold the rights to Thurman Baird in 1965 who operated the Ace Aircraft Manufacturing Company. Baird also had the rights to the Heath Parasol aircraft, among several other experimental aircraft designs.
I have the original Corben Baby Ace dimensions and performance with Salmson 45 and the model D dimensions and performance with Continental A65 and with Continental C65. If yours is the C model N85Y, you could then measure and compare all the changes from original to model C and to the model D with two different engines. I believe the C model is now fairly rare. Let me know.