Hasselblad 503 CW Polaroid back for 3 1/4" x 4 1/4" pack film

[waichoy]

I recently rented a Hasselblad 503 CW with polaroid back and was disappointed to find that the image exposed on the polaroid film was 6 cm x 6 cm and did not fill up the full polaroid image are.

I know that this is because the Hasselblad has a 6 cm x 6 cm image area, but is there anything I can get for the 503 CW that would let the image expose onto the entire polaroid?

If not, what kind of Camera and back would I need to expose the whole area?

Please help!

Thanks.