
I don't think the Omega will fit, if it was a 73 or 74 it would. The nova disc conversion uses disc set-ups from a lot of GM cars from 69 to 74. After 73/74 there was a magor change in brake design. 62 to 72 Novas can use :
Buick 69-72 Century, Regal, Skylark, Special, GS
Chevrolet 69 Camaro, 69-72 Chevelle, El Camino, Malibu
69-74 Chevy II, Nova, Concours
OLDS 69-72 Cutlass, F85, 442, Vista Cruiser
Pontiac 69 Firebird, 69-72 Grand Prix, GTO, Lemans, Tempest, Grand Am 71-74 Phoenix, Ventura
GMC 69-74 Sprint, Caballero
If you can find any of these disc brake car at the local wrecking yard, the swap is pretty easy. Also if you pull these get the master cylinder and proportioning valve, and rubber brake hoses.
I just completed a conversion on a 1962 Chevy II.
hope this helps.