  A numerical study of Orientifold Planar Equivalence is performed in SU(N)
Yang-Mills theories for N=2,3,4,6. Quenched meson masses are extracted in the
antisymmetric, symmetric and adjoint representations for the pseudoscalar and
vector channels. An extrapolation of the vector mass as a function of the
pseudoscalar mass to the large-N limit shows that the numerical results agree
within errors for the three theories, as predicted by Orientifold Planar
Equivalence. As a byproduct of the extrapolation, the size of the corrections
up to O(1/N^3) are evaluated. A crucial prerequisite for the extrapolation is
the determination of an analytical relationship between the corrections in the
symmetric and in the antisymmetric representations, order by order in a 1/N
expansion.
