Surprisingly, Stanford University hosts a gallery of photos from the 1968 NHRA Spring Nationals at Englishtown. There's lots of S/SS shots plus a variety of other classes and some pit photos, too. At the very end there are a few from Indy 1974.
https://revslib.stanford.edu/?page=1...utf8=%E2%9C%93
ps. You could spend days at that site. there are over 175,000 automotive images overall