[Gearhead999]

The 67 and 90 seats are not going to just interchange. You'll have to do some fitting.

I'd first try the 90 seats and rail to the 67 body. Set the seats, with the rails attached, in the car and see where they sit, are they level? Are they tall enough?
Are they too close or too far away from the steering wheel and pedals? Be careful, but sit on the seat while it's sitting in the car. See how it feels and fits.

You can go from there and see what you have to do to make them fit. Don't forget the seatbelts too.

When you finally get the seats where you want them and all. Be sure that you reinforce the mounting points so the seats don't just rip out of the floor, incase of a collision.

Nothing looks worse then some seats just half a$$ bolted into a car. All crooked and out of position. And worse is mounted to 2 X 4's.

Do it right or not at all.