The cost of a Big Mac in 1986 was $1.6 according to the Economist's Big Mac Index dataset[0]. The minimum wage in 1986 was $3.35[1] according to the US Department of Labor.
So you could afford at most two Big Macs in 1986, not seven. Also you can definitely afford one big mac with an hour of minimum wage today (minimum wage: $7.25, big mac: $5.36).
0 - https://github.com/TheEconomist/big-mac-data/blob/master/sou...
1 - https://www.dol.gov/agencies/whd/minimum-wage/history/chart