103 is the EAA's XP-51....and that background sure looks like Oshkosh to me.
William D. Yoak
This looks like the good ol' XP-51A that has been part of the EAA Collection at Hales Corners, Wisoconsin for several years.The aircraft had been operated by Paul Poberezny (founder of EAA) on occasion for several years. I presume that it is still included in the EAA Museum.
This is XP-51 #41-038, N51NA. Restored for a first flight in 1976 it was retired to the museum in 1982.
This is of course, the EAA's XP-51, N51NA serial 41-038. It on display in the EAA Museum at Oshkosh.