This was a very popular swap on '56 Fords back in the day, but I don't know about on a '55. I'd expect you'd need to fabricate some brackets and perhaps some minor sheet metal changes. I think the final results would be very much worth the effort. I'll post some photos of this swap when I find them. Here's an image that might help. Even though the text says '56 Ford, I think this is actually a '55 Crown Vic. I'll repost a larger image which may show more detail.
Here's a nice big image of the swap you mentioned. There's no technical information, but the photos may help. Good luck!
I agree with you Eric, it's a '55. The side moldings are definitely '55 but unless he changed out the dashboard, the real giveaway is the round radio. Grille openings are similar on both years, I'd guess the mod to accomodate the Merc would be about the same? Ron