Pontiac made a bunch of different 14 x 6 Rally II wheels, and it can get very confusing.
If your kit is aftermarket, it just might be that no 14" will fit. However, if your kit uses alot of GM parts, there just might be a wheel that will fit.
In 1967, the first 14 x 6 Rally II wheels were "JA" and "JC" code. JA was meant for the disc brakes of that year, although the JC will fit those disc brakes too.
There are a couple other codes in '68 and '69 and '70 that will fit the discs, such as the JL code Rally II wheel I think.
The two problems with fitting a wheel around calipers is the radial height of the caliper, as well as the thickness (how far it sticks out toward the outside of the car).
Pontiac fiddled with two elements of the wheel "assemblies" to fit various applications: The wheel hoop (rim) and the wheel center (the spoke section)
The JA wheel mentioned above has a wheel "hoop" that accommodates the radial height of the 4 piston caliper, and the wheel center lug pockets are deep enough to keep the wheel center away from the wide caliper body. The JA wheel was used on the new-for-69 Pontiac A body single piston caliper disc brakes.
And, oddly enough, the "JC" wheel I mentioned was intended for drum brake cars, but I have personally tested them on disc brake (stock) rigs, and they fit.
After 1970, Pontiac changed the Rally II wheel center lug pocket shape to be less deep...so they won't fit wide (4 piston) caliper cars...they will only fit single piston set ups used in the 70's on up.
So, for your situation, there is still a risk even the JA, JC, or JL 14 x 6 wheel won't fit because you have aftermarket stuff. It still might be worth a try though....perhaps you know someone local who can let you trial fit one of those wheels?