I have a vague memory of seeing a late 1960's NASCAR that had a hole cut in the lower right corner of the front firewall, so that the driver could visually see how much wear the right front tyre had left, in order to know when to pit for a tyre change.
Would someone be able to post a picture of this to confirm my memory? Also, was this a NASCAR rule, or did individual drivers cut out the hole for their own safety and peace of mind?
Edited by Graham Clayton, 16 March 2012 - 00:02.