I believe that it would be 14 inches by 5.5". Are you talking about the bolt spacing or rim size? The bolt size i think it 4 lug 4 1/2" spacing between bolts. I still have the steel wheels off of my '84 LX and they're 14x5.5 and came stock with P195/75R14 tires. I hope this helps.
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previous name: 84stangLX
'84 Mustang 5.0 LX
my LX
'89 Mustang GT
my GT