Geez Rob, there's a lot of snow out there. I don't think the 37 Chevy frame is much narrower than the 40 Ford. If the frame does fit between the bottom mounts weld a piece to the bottom of the frame that will sit on and bolt to the Fiero mount. The 37 Chevy has a boxed frame and it may be more difficult to bolt the bottom mount to the frame. You would have to cut some access holes in the side of the frame to put nuts on.

AS for rotors, I haven't tried any others but I think if there are others that fit the spindles they would most likley be from other GM cars from the eighties like the Camaro or S10. A five bolt rotor is easier to redrill to a different bolt pattern than a 4 bolt. But I don't recall if the rotor is big enough to redrill. I would have to dig it out, jack it up and take off a wheel. According to the news it was 17 below zero last night. so I'm waiting till the end of March before I go outside again unless Bob finds room for me in Vegas.