here's a cross to a Hays number.

http://aftermarket.hayes-lemmerz.com/html/app_mercury.html

I posted this data nearly a year ago about these rims, so here it is
again.

....future reference is what I found....

Stock '53 rim:

Tire bead inside Width:                   5"
Overall outside width:                    6-1/8"
Backspacing:                              4-3/8"
Offset (tire centerline to inside edge):  1-5/16"
Center hole ID:                           2-3/4"

Stock '63 lark rim:

Tire bead inside width:                   4-1/2"
Overall outside width:                    5-5/8"
Backspacing:                              3-5/8"
Offset (tire centerline to inside edge):  1-1/16"
Center hole ID:                           forgot to measure

6" Ford rim, NWRA X-40273:

Tire bead inside width:                   6"
Overall outside width:                    7-1/8"
Backspacing:                              4-1/8"
Offset (tire centerline to inside edge):  9/16"
Center hole ID:                           2-3/4"

Currently, my '53 has a stock mid 70's Maverick 8" rear end in it.
With the stock '53 rims, my track width from center to center of the
rear tires is about 54-1/2" to 54-3/4".  I have 205/75R15 tires on it
and there is about 3" to 3-1/2" clearance from the tire sidewall to the
fender lip on each side.

While at the zone meet in WI last month, I took the opportunity to
check out some other cars.  There was a '54 Champion hardtop there with
stock sized bias tires (6.70-15).   I'll assume it had the stock wheels
since everything else about it was stock....  Track width was 56-1/4"
center to center and about 2 to 2-1/2" clearance from the sidewalls to
the fender lips.  I also checked the rear track on a '58 packard hawk
and it was also 56-1/4".

Soooo.  It would appear that the Maverick rear end is about 1-1/2" to
1-3/4" inches narrower than the original rear was in my car.  Taking
into account the rim width and change in offset, if I put these wider
rims on the back, I should increase my track width about 1-1/2" and get
back what was lost.  The outside of the wheel should push out 1-1/4"
over what I have now and will make my fender clearance essentially the
same as the stock setup was like I measured on that '54.

I currently have the rims on my car and the tires fit better.  My car
has the finned drums on front so I can't comment about disk brake
clearance.  The only thing that may cause issue is I had to change the
caster on the front end since the rims apparently changed the "scrub
radius" and made the handling a little darty on the highway.  See some
other recent posts about that.

As far as the rear fender clearance, you should be able to measure what
you have now and use the above dimensions to calculate where it will be
with the wider rims.  In my case, my brand X rear was narrower than
stock so it was not a issue.  I was actually hoping to make it tighter.

Hope this helps,
Jeff