The house that seemed affordable with no car payment was a little over $9K (down payment of $1800). Adding in a $50/mo car payment took the affordable house down to a little over $8K, less than half the price of the median home in 1970.
Was there a minimum wage worker sometime in 1970 who bought a house and a newish car? I'm sure there was. Was it typical to do so? I don't think so.
Refs: http://www.freddiemac.com/pmms/pmms30.html , https://news.ycombinator.com/item?id=29590190 , https://www.bankrate.com/calculators/mortgages/new-house-cal... (I used a 10x multiplier, so I modeled in the calculator someone making $14.50/hr, a median house of $170K rather than $17K, etc, and then divided them by 10 to cite the figures above.)