A nice photo here showing the two in formation:
Crosswind Images | Warbirds & Classics | Nanchang CJ-6 and YAK 52
The big differences are the dihedral on the outer wing panels of the CJ-6, giving it a slightly gull-winged appearance and the squared-off fin and rudder. The bubble canopy of the the CJ-6 in this photo is non-standard.