They also had 22.000 to win races. Also not a very fair comparison to todays car owners.
Seen a pic last week of a mid 70s Hoosier Hundred winner standing with a big well over 20,000g check

Heres a article where the HH paid a 68,000 purse and the motors probably costed 6 grand, Today the rebuild is more than that.
http://sportsillustrated.cnn.com/vau...15/1/index.htm