Biggest Rear Tire Size

Here is the specs for the Mickey thompsons SRs you want to run:
And the specs on the now discontinued M/T L60-14's on I believe 7" rims of unknown offset (really need to be 8's to 8.5's though) that my son has on his 72 Demon:

-----------------approved----measuring--sidewall--tread---diameter
-------------------rims--------rim--------width----width
28X12.00R15LT--8.5-10.0------10---------12.0-----10.4-----28.0

L60-14's---------7-10.0---probably 10-----12.3-----9.5------28.0
(295/60/14)
Here's some pics, the sidewall to leaf spring is VERY tight, but the tire width and diameter fits the car Very well in my opinion.