The 44 "Navy" is a 44
army made with a Navy like octagonal barrel. The frame is the same as the 1860 Army in that it has a rebated front portion of the cylinder cut to accept the stepped Army cylinder with its larger forward end to accept 44 caliber.
If you put a Navy 36 cylinder and barrel on the gun, there will be a space under the forward half of the 36 (or conversion such as Kirst or R&D) cylinder, and if that larger gap doesn't bother you appearance wise, it all works. Navy cylinders and barrels will fit an Army (1860) frame (given minor fitting), because even two Navies or two Armys have to be "adjusted" in the fit to the wedge, the two barrel pins and the cylinder pin fit. I put the Kirst Konverter and Navy barrel from my 36 on a 2nd Gen Colt 1860 Army 44, and given it was a bit tight in a spot, could easily fit, function and fire.