Yes, the spindles and calipers will work on a 1967. A disc brake conversion includes much more than that though.
Brake pedal can be from any year, 1967, 1968, 1969, or 1970. Booster push rod must match the disc brake pedal though. No need to change pedal if you have 1967 with power drums.
You need to trim the firewall, best to change the pedal hanger bracket to the disc brake version. Hard lines and rubber lines need to be changed, I would use the 1970 disc brake proportioning valve/distribution block.
Don't forget to use a disc brake, brake pedal switch.
Are you running stock 14" wheels on your 67 ?
... not sure if I remember this correctly ... about 20 years ago, when I was going to take the disc brakes from my friend's wrecked 69 'stang, I tried my stock 14" wheels on his car before I started pulling parts.... the 14" wheels would not fit on 69 mustang disc brakes .... so I wouldn't be surprised if a 70 cougar's brakes are the same ...
Not sure if it matters / helps... but I pulled my spindles, calipers, rotors, etc.. off of a Granada and bolted them on, and am using my stock non-power pedal and pushrod w/ no modifications. Running a mid 80's SVO master cyl for non-power discs ... they feel great.
Thanks guys..........I am getting all the parts from the donor car..........I have new 15" wheels so they won't be a problem............ Here's a picture of the car....Hard to see the metallic in the picture...........